EARTHQUAKE 
 
 INVESTIGATION 
 
 in the United States 
 
 C&GS SPECIAL PUBLICATION NO. 282 
 Revised (1969) Edition 
 
 U.S. DEPARTMENT OF COMMERCE 
 Environmental Science Services Administration 
 
Digitized by tine Internet Arciiive 
 
 in 2012 witfi funding from 
 
 LYRASIS IVIembers and Sloan Foundation 
 
 http://archive.org/details/earthqual<einvestOOcoff 
 
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 EARTHQUAKE 
 
 INVESTIGATION 
 
 in the United States 
 
 C&GS Special Publication 282 
 Revised (1969) Edition 
 
 U.S. DEPARTMENT OF COMMERCE 
 
 Maurice Stans^ Secretary 
 
 Environmental Science Services Administration 
 Robert M. White, Administrator 
 
 Coast and Geodetic Survey 
 Don A. Jones, Director 
 
Issued by the 
 
 National Earthquake Information Center 
 Rockville, Maryland: 1969 
 
 Revised Edition by 
 Jerry L. CoflFman 
 
 For sale by the Superintendent of Documents, Government Printing Office 
 Washington, D.C. - Price 35 cents. (Paper Cover) 
 
CONTENTS 
 
 Page 
 
 Introduction 1 
 
 Seismological Organizations 1 
 
 National Earthquake Information Center 4 
 
 World Earthquakes 5 
 
 Earthquakes in the United States. : 7 
 
 Eastern Region 7 
 
 Mississippi Valley Region 11 
 
 Western Mountain Region 12 
 
 Pacific Coast and Nevada 13 
 
 Alaska 17 
 
 Hawaii 17 
 
 Puerto Rico and Panama Canal Z^ne 18 
 
 Tsunami Warning Service 19 
 
 Tsunamis 19 
 
 What to Do During an Earthquake 21 
 
 Nature of Earthquakes and Seismic Waves 24 
 
 Seismographs . . . . , 30 
 
 Descriptive Reports on Earthquakes 36 
 
 Engineering Seismology 38 
 
 Microseisms 43 
 
 APPENDIX 
 
 Table 1 . — Active teleseismic stations of the United States . 45 
 
 Table 2. — Lives lost in major United States earthquakes . 51 
 Table 3.^ — Damage (in dollars) caused by strong United 
 
 States earthquakes 52 
 
 Seismological Puolications of the National Earthquake 
 
 Information Center 53 
 
 lU 
 
ILLUSTRATIONS 
 
 Page 
 
 Figure 1 .■ — General trend of the earthquake belts of the 
 
 world 6 
 
 Figure 2a. — Damaging earthquakes of the United States 
 
 through 1968 8 
 
 Figure 2b.- — Selected earthquakes from fig. 2a, with 
 
 locations and years of occurrence given . 9 
 
 Figure 3.' — Earthquake waves recorded on typical 
 seismogram and paths of propagation 
 through the earth 27 
 
 Figure 4. — Travel-time curves with idealized seismo- 
 
 grams superimposed 28 
 
 Figure 5.- — Geophysicists of the National Earthquake 
 Information Center illustrating tech- 
 nique of locating an earthquake on a 
 32-inch globe 29 
 
 Figure 6.' — Modern seismograph system as used in the 
 Network of Standard Seismograph Sta- 
 tions 31 
 
 Figure 7.- — An assembly for visible-recording seismo- 
 graph 32 
 
 Figure 8.- — College, Alaska, seismogram showing re- 
 cording of earthquake on February 22, 
 1958, in Aleutian Islands 33 
 
 Figure 9. — Coast and Geodetic Survey accelerograph . . 34 
 
 Figure 1 0. — Typical intensity map prepared for stronger 
 
 earthquakes of the United States 35 
 
 Figure 1 1 .• — Ferndale accelerogram of California earth- 
 quake, December 10, 1967 39 
 
 Figure 12. — Coast and Geodetic Survey seismoscope. . . 41 
 
 Figure 13. — Seismoscope record produced by instru- 
 ment in fig. 12 42 
 
 Figure 14.- — Seismogram showing microseismic storm in 
 
 December 1956 at Sitka, Alaska 43 
 
 IV 
 
 I 
 
EARTHQUAKE 
 
 INVESTIGATION 
 
 in the United States 
 
 Introduction 
 
 To the layman, earthquakes are generally considered a very 
 unusual type of natural phenomenon — an indication that 
 something occasionally goes wrong deep down in the earth. 
 To the seismologist who studies earthquakes from their scien- 
 tific viewpoint, they represent a process of nature as unceasing 
 and routine as the winds that blow over the oceans. The pur- 
 pose of this booklet is to explain the more important facts of 
 earthquake phenomena and outline the role played by the 
 Federal Government and various seismological organizations 
 in dealing with the scientific and economic aspects of the earth- 
 quake problem. 
 
 Seismological Organizations 
 
 The Coast and Geodetic Survey, now a part of the Environ- 
 mental Science Services Administration, is the U.S. Govern- 
 ment agency authorized by law to make investigations in 
 seismology. Other organizations, however, are also engaged 
 in such work. One of these, the Jesuit Seismological Associa- 
 tion in St. Louis, Mo., coordinates the work of 23 affiliated 
 
 1 
 
seismological stations spread over most of the country. The 
 California Institute of Technology operates 18 stations in 
 southern California for the intensive study of earthquakes in 
 that area, and the University of California operates a somewhat 
 similar network of 20 stations in the northern California area. 
 In addition, about 49 independent stations are operated by 
 universities in connection with their geological and geophysical 
 programs (see table 1 ) . 
 
 One of the seismological functions of the Coast and Geodetic 
 Survey is to serve as a clearinghouse for much of the statistical 
 data and other information collected by these groups, to pub- 
 lish summaries of the data, and to establish seismograph sta- 
 tions where necessary to provide more complete instrumental 
 coverage of earthquakes. In the collective efTort to locate 
 accurately earthquakes in the United States and elsewhere, the 
 Survey operates 35 stations of its own (see table 1) and 
 actively cooperates in the maintenance of several others (mostly 
 university stations) . 
 
 Since 1960, earthquakes have been located by means of an 
 electronic computer. An accumulation of about 15,000 global 
 earthquake observations (arrival times) are fed into the com- 
 puter twice weekly and within 15 minutes, hundreds of earth- 
 quake epicenters are located. Previous to computers, the 
 location of a similar number of earthquakes would have taken 
 Survey seismologists several days. 
 
 The Survey also operates a strong-motion seismograph net- 
 work in the western United States, Central and South America. 
 These instruments, inactive until triggered by earth movement, 
 are installed in all types of buildings and structures. The records 
 of strong earth motion provide architects and engineers with 
 data essential to the design of safer structures and the establish- 
 ment of better building codes and safety regulations. 
 
 It will subsequently be shown that, far from being ex- 
 clusively of academic interest, the results of this concerted 
 effort are of practical use to many professional groups — the 
 insurance actuary who wants to know exactly where and to 
 what degree earthquake dangers exist; the structural engineer 
 who wants to know the magnitude and nature of the earth- 
 quake forces he must design structures to resist; the geologist 
 
who endeavors to associate seismic activity with the faults 
 mapped in the course of field surveys; and the meteorologist 
 who wants to know just how the minute vibrations of the 
 earth's surface are related to storms and other meteorological 
 phenomena. In the academic field, the study of seismic wave 
 propagation has furnished the most authentic information 
 yet obtained on the physical nature of the earth's interior. The 
 study of earthquake waves has also furnished the basic 
 concepts used in locating oil-bearing structures by seismic 
 exploration methods. 
 
 The program of the Coast and Geodetic Survey is a repre- 
 sentative amount of the seismological studies conducted in 
 this country and includes projects of a specialized nature. Be- 
 sides operating seismological stations to record earthquakes, 
 the Survey collects statistical information on all types of earth- 
 quake phenomena, including dollar value of property damage; 
 prepares earthquake catalogs and epicenter maps; and conducts 
 various types of investigations directed toward a better under- 
 standing of earthquakes. 
 
 A very important phase of the Survey's seismological pro- 
 gram is the investigation of destructive earthquake motion, a 
 program of basic importance to the engineer who must design 
 structures to resist earthquake forces. The 700 persons killed 
 in the great California earthquake of 1906 and the billion-dollar 
 (present-day value) property loss caused by the ensuing fires 
 will always stand as a warning to those who feel that the earth- 
 quake menace can be ignored. Years of study have shown that 
 the problem of the design engineer is technically difficult, be- 
 cause earthquake forces are vibrational (dynamic) in character 
 and cannot be treated the same as static (steady) forces. Much 
 has been accomplished, however, and the Survey has played 
 an important role in this accomplishment by furnishing 
 authentic information on destructive ground and building 
 motions. 
 
 An interesting phase of seismological research is its interna- 
 tional aspect. The fact that a strong earthquake in any country 
 is registered on seismographs all over the world has resulted 
 in a worldwide exchange of data and cooperative eff'ort that is 
 
matched in few other fields. This international exchange of 
 information has resulted in a great accumulation of technical 
 data that has not only made possible an authentic history of 
 world earthquakes over the past 65 years, but, after exhaustive 
 analyses of the data, has given the scientific world the most 
 accurate picture available of the physical structure of the earth's 
 interior. 
 
 National Earthquake Information Center 
 
 On August 15, 1966, the National Earthquake Information 
 Center (NEIC) was established in Rockville, Md., to provide 
 an improved source of information for the public, as well as 
 technical users. The first new service was the Earthquake Early 
 Reporting System, developed to inform the public, disaster 
 relief agc^icies, and scientists of magnitude 6^2 or larger earth- 
 quakes 7^"^ quickly as they are located — usually within 2 or 3 
 hours. Smaller events are located on receipt of a press report 
 of damage. 
 
 The global facilities of the Coast and Geodetic Survey — its 
 seismograph stations and cooperating observatories — are used 
 to provide information for the system. When a large earthquake 
 occurs, the participating observatories telephone or telegraph 
 their observations to the National Meteorological Center at 
 Suitland, Md. This information is relayed to a duty seis- 
 mologist at NEIC who locates the epicenter graphically on a 
 large world globe and scales the magnitude. For U.S. earth- 
 quakes, felt reports are also received from a network of 300 
 Weather Bureau stations. These facts, together with back- 
 ground and explanatory comments for nonseismologists, are 
 released via Weather Bureau circuits and directly to news 
 media. 
 
 The NEIC serves as a focal point for numerous additional 
 seismological services, such as the Preliminary Determination 
 of Epicenters program which, using a high-speed computer 
 and tens of thousands of recorded observations, annually 
 locates about 6,000 earthquakes within a matter of a few weeks 
 after the earthquakes occur. 
 
Another service is the preparation of seismic histories for 
 engineers, actuaries, and scientists. Extensive files of past earth- 
 quakes, including an IBM card file of more than 50,000 in- 
 strumentally located earthquakes of the past 70 years, are 
 maintained at the Center for this purpose. 
 
 The Center provides a focus for direct inquiries from the 
 whole spectra of groups needing earthquake information, in-' 
 eluding engineers, actuaries, teachers, students, and the general 
 public. 
 
 World Earthquakes 
 
 It is estimated that several million earthquakes occur an- 
 nually throughout the world. They range from minor tremors 
 that are barely perceptible locally to catastrophic shocks. For- 
 tunately, most earthquakes originate beneath the sea where they 
 cause little concern except when seismic sea waves (tsunamis) 
 are generated. Such waves occasionally cause damage and loss 
 of life thousands of miles away, as well as near the earthquake 
 origins. Approximately 700 of the shocks each year may be 
 classed as strong, i.e., capable of causing considerable damage 
 in the areas where they occur. The Coast Survey's National 
 Earthquake Information Center, with the cooperation of many 
 foreign and domestic agencies, locates each of these larger 
 shocks within a few hours. The annual epicenter maps that pin- 
 point the locations are illuminating exhibits, showing where 
 most earthquakes occur. One is struck not only by the existence 
 of certain well-defined seismic belts stretching over large areas 
 of the world, but also by the persistence of the overall pattern 
 for any selected period of time. Figure 1 shows the general 
 trend of the world seismic belts. 
 
 The rim of the Pacific Ocean outlines the world's greatest 
 seismic belt. Known as the circum-Pacific belt, it includes the 
 Aleutian Islands, southern Alaska, and the Pacific coast of 
 the United States. A second major belt, known as the Alpide, 
 branches off to the west and extends across the southern por- 
 tion of Eurasia, through the Mediterranean, and to the Azores 
 
 335-146 O— 69 2 5 
 
in the Atlantic Ocean. There are also many minor belts, such 
 as that looping eastward from the Pacific through Mexico, 
 the West Indies (including the Windward Islands), and those 
 countries bordering the southern shores of the Caribbean Sea. 
 Earthquakes in these belts are taken for granted, but great 
 shocks also occur occasionally in other areas. Examples in this 
 country are southeastern Missouri and Charleston, S.C. How- 
 ever, many years usually elapse between destructive shocks in 
 these atypical regions. This brief discussion therefore shows that 
 the cities of our Pacific coast are not alone in their vulnerabil- 
 ity to destructive earthquakes, for the menace also exists in 
 many areas ordinarily considered to be only moderately seismic. 
 
 Earthquakes in the United States 
 
 The earthquake history of the United States is outlined in 
 Publication No. 41-1, Earthquake History of the United States, 
 Parts I and II. Part I covers the United States, exclusive of 
 California and western Nevada, and Part II describes the 
 stronger earthquakes of only California and western Nevada. 
 Both volumes are available from the Superintendent of Docu- 
 ments, Government Printing Office, Washington, D.C. 20402. 
 
 Information on recent earthquakes may be found in the 
 annual issues of the United States Earthquakes series, also 
 published by the Coast and Geodetic Survey. The following 
 is a summary of the earthquake history of the United States 
 based on information appearing in these publications (see 
 tables 2 and 3 for lives lost and resultant damage in major U.S. 
 earthquakes). Figure 2a shows the locations of all damaging 
 (intensity VII and above) earthquakes of the United States. 
 Figure 2b names most of the important shocks discussed in this 
 publication and gives the years in which they occurred. 
 
 Eastern Region. — The earliest recorded earthquake of de- 
 structive intensity observed in the United States occurred in the 
 St. Lawrence River region in 1663, apparently centering be- 
 tween the present sites of Montreal and Quebec. Great land- 
 slides kept the river muddy for a month. A less severe 
 
earthquake centered in the same general region in 1870 and 
 was felt as far south as Virginia, but damage in the epicentral 
 area was comparatively light. Another shock, centering 300 
 miles west of this area near Timiskaming, Canada, shook most 
 of the northeastern part of the United States on November 1, 
 1935. On September 5, 1944, a shock centering close to 
 Massena, N.Y., and Cornwall, Canada, caused $2 million 
 damage in these towns. 
 
 Various parts of New England have experienced moderate to 
 severe earthquakes, some of sufficient intensity to damage 
 houses, and especially chimneys. The most severe was the shock 
 on November 18, 1755, that centered east of Cape Ann, Mass. 
 Many chimneys were thrown down or twisted and roofs were 
 wrecked as a result. In 1791 there were strong shocks near East 
 Haddam, Conn., and for years the area was noted for sub- 
 terranean noises of seismic origin. On November 18, 1929, all 
 of New England was shaken by a strong submarine earthquake 
 off the Grand Banks of Newfoundland. A coastal area extend- 
 ing from Richmond, Va., to Portland, Maine, and inland as 
 far as northwestern Pennsylvania, was shaken on August 10, 
 1884, by an earthquake that apparently originated near the 
 edge of the Continental Shelf off the mouth of the Hudson 
 River. On Long Island, walls and plaster were cracked at 
 many places. The lake region of northeastern New York has 
 experienced several shocks strong enough to damage chimneys. 
 On August 12, 1929, Attica, located in the western part of the 
 State, experienced a shock that knocked down 250 chimneys. 
 
 In New Jersey, Pennsylvania, and the States to the south, 
 occasional strong but nondestructive shocks are believed to be 
 the result of the settling of the coastal plain sediments on the 
 underlying basement rock that structurally represents the base 
 of the Appalachian Mountains range. In 1897 one of the 
 strongest of this type occurred in Giles County, Va., where old 
 brick houses and chimneys were cracked. It was felt as far as 
 Indiana and Georgia. 
 
 The greatest shock in the East was the Charleston, S.C., 
 earthquake of August 31, 1886. It was felt as far as Chicago 
 and Boston. In Charleston, 60 persons were killed and many 
 
 10 
 
buildings were ruined or severely damaged. In the surrounding 
 country, bridges were wrecked, railroad tracks were twisted, 
 and sand and water were ejected from numerous craterlets. 
 
 Mississippi Valley Region. — Although this region is sub- 
 jected to frequent small earthquakes, it has not experienced a 
 major shock since those of December 1811 and January and 
 February 1812 which were among the greatest shocks this coun- 
 try ever experienced. The first of these is rated as one of the 
 great earthquakes of known history. They centered near New 
 Madrid in southeastern Missouri and were felt over two-thirds 
 of the United States. With this area of the country now so 
 densely populated, one can only conjecture what might happen 
 if similar disturbances were repeated. Evidence exists that there 
 was a similar earthquake in the same region about 100 years 
 prior to the 1811 shock. A lasting result of these disturbances 
 was the lowering of a large part of the countryside in south- 
 eastern Missouri and northeastern Arkansas, now known as the 
 "sunken country." 
 
 Severe shocks were reported from this general area in 1843 
 and 1895, and hardly a year has passed without some dis- 
 turbance being noted. The 1843 shock was felt strongly in St. 
 Louis, Mo.; Frankfort, Ky.; Cincinnati, Ohio; and Nashville, 
 Tenn. In 1895 a lake was formed over four acres of ground 
 that sank near Charleston, Mo., and many chimneys were de- 
 molished. Near Bertrand, sand was ejected from the ground 
 and the water table was apparently raised. The shock was felt 
 in 23 States. In 1963 an earthquake centered in southeastern 
 Missouri knocked bricks from chimneys and cracked walls, 
 foundations, and sidewalks. It was felt over 100,000 square 
 miles of nine States. A similar shock in 1965 caused minor 
 damage in several towns and was felt over a 160,000 square- 
 mile area. 
 
 Southwestern Indiana is a center of moderate seismic 
 activity. The central portion of western Ohio has experienced 
 five strong shocks since 1875, most of which cracked some walls 
 and toppled a small number of chimneys. Other centers of 
 moderate activity are found scattered through Illinois and gen- 
 erally west of the Missouri River in eastern Nebraska and 
 
 11 
 
Kansas. A magnitude 5.3 earthquake occurred in southern 
 IlHnois near the Indiana border on November 9, 1968. It was 
 felt over approximately 500,000 square miles, including 23 
 States. Minor chimney damage, cracked walls, broken win- 
 dows, and fallen plaster occurred in Illinois, Indiana, Missouri, 
 Kentucky, and Tennessee. 
 
 Western Mountain Region. — Excluding Nevada, the prin- 
 cipal seismic zone in this area extends in a broad band from 
 Helena, Mont., southward to northern Arizona. In 1925 violent 
 shocks in the region of Manhattan and Three Forks, Mont., 
 cracked many buildings, toppled chimneys, and caused land- 
 slides that blocked the main line of the Chicago, Milwaukee & 
 St. Paul Railroad for many days. In 1935 two destructive 
 earthquakes centered close to Helena. In 1959 an eight-State 
 area and British Columbia experienced the Hebgen Lake, 
 Mont., earthquake in which 28 people were killed by the great 
 Madison Canyon slide. Surface damage extended 50 miles 
 westward from Yellowstone National Park, and damage esti- 
 mates to timber and roads exceeded $11 million. 
 
 At Elsinore, Utah, 150 miles south of Salt Lake City, a series 
 of strong shocks in 1921 damaged half the buildings, knocked 
 down many chimneys, and wrecked a school building. In 1934 
 a strong shock centering near Kosmo, Utah, caused many 
 craterlets to form in the ground, cracked walls and chimneys 
 locally, and caused some plaster to fall in Salt Lake City. 
 
 In New Mexico, a long series of disturbances near Socorro 
 reached a climax in 1906 when a brief series of strong shocks 
 cracked some adobe walls and toppled others. In 1966, a 
 moderate shock in the New Mexico- Colorado border region 
 damaged many structures in Dulce, N. Mex., and caused minor 
 damage at Edith, Colo. Several small ground cracks appeared 
 in the fill across the frozen roads in the Dulce area. Dulce 
 Point had a complete change in configuration by the collapse 
 of huge masses of shale and sandstone. 
 
 The Panhandle area of Texas has experienced a number 
 of widespread but nondestructive shocks. In 1931, southeast 
 of El Paso in the Great Bend area, a violent shock near Valen- 
 tine badly damaged all types of buildings and knocked down 
 
 12 
 
 I 
 
many chimneys. It was felt over the entire State. Large quanti- 
 ties of water were emitted from cracks and craters that formed 
 in the ground. Across the border in the State of Sonora, Mex., 
 an earthquake in 1887 destroyed the church at Bavispe and 
 damaged many other buildings. Great numbers of cracks 
 emitted sand and water, and millions of cubic feet of rock were 
 thrown down mountains. From Guaymas to Nogales, Benson, 
 Tucson, El Paso, and as far away as Albuquerque, water in 
 tanks splashed over the sides, chimneys fell, and buildings 
 cracked. 
 
 Pacific Coast and Nevada. — Much of the seismic activity 
 of the country is centered in this area, principally in the Coast 
 Ranges of California. Some of the most outstanding historic 
 earthquakes include one in 1812 in the Santa Barbara- Ventura- 
 northern Los Angeles County region; one in 1838 along the 
 San Andreas fault near San Francisco; another in 1857 in 
 the northwest comer of Los Angeles County; one in 1872 in 
 Owens Valley in the Sierras; and finally, the earthquake of 
 1906 which resulted in the destruction of a large part of San 
 Francisco by fire. Other large earthquakes in this area include 
 two that originated along the Hayward fault just east of 
 the southern half of San Francisco; two submarine shocks off 
 the northern coast of California; two in Nevada; and one each 
 in the Los Angeles area, in Owens Valley, in Baja California 
 ( Mexico ) , and in Imperial Valley. These were not necessarily 
 the most notable earthquakes, because many of them expended 
 their violence either in isolated mountain and desert regions 
 or on the ocean floor. When the 1838 earthquake struck the 
 Bay area, San Francisco was little more than a scattering of 
 huts and crude structures of the early pioneers. 
 
 The California earthquake of April 18, 1906, was the most 
 notable, in terms of lives lost and property damage, of all earth- 
 quakes in this country. Seven hundred lives were lost, and San 
 Francisco was practically razed by fires that followed shortly 
 after the earthquake. The city burned unchecked for days due 
 to the wrecking of the water supply system. Actual earthquake 
 damage probably did not exceed $24 million (1906 dollar 
 value), but the fire increased this, perhaps twentyfold. This 
 
 335-14)6 O— .69- 
 
 13 
 
scene of disaster was duplicated on a smaller scale in many other 
 California cities and towns. 
 
 The 1906 earthquake was the result of shifting along a great 
 rift that extends from Imperial Valley, just north of the Mexi- 
 can border, northwestward through the Coast Ranges to Golden 
 Gate. A short distance north of Golden Gate it passes out to sea 
 through Tomales Bay, an elongated bay apparently formed 
 by repeated movements along the fault over a long period of 
 years. The maximum horizontal slipping in 1906 was 21 feet. 
 Vertical slipping was only a small fraction of this. Along the 
 fault, fences and roads were sheared and separated many feet 
 by the irresistible force of the earth movement. Structures built 
 on the fault were wrenched and ruined. A brief summary of 
 other notable earthquakes in the California-Nevada area 
 follows. 
 
 On October 21, 1868, almost every building in Hayward 
 was damaged by a slip along the Hayward fault. Property 
 damage in San Francisco reached $350,000. In 1872, all adobe 
 houses were wrecked and 27 persons out of a population of 
 about 300 were killed at Lone Pine located in Owens Valley. 
 Practically all brick buildings were wrecked in Vacaville by 
 an earthquake in April 1892. On Christmas Day of 1899, 
 nearly all brick buildings in San Jacinto and Hemet were dam- 
 aged, with only two chimneys left intact in Hemet, and six 
 persons were killed. The same towns experienced another 
 shock in April 1918 that wrecked all poorly constructed build- 
 ings in the business areas and caused more than $200,000 
 property damage. Inglewood experienced a highly localized 
 disturbance which wrecked many buildings in June 1920; few 
 structures escaped damage. On June 29, 1925, Santa Barabara 
 sustained several million dollars damage from an earthquake 
 that left few buildings on the main street undamaged. This dis- 
 turbance, which killed 13 persons, was caused by a fault slip 
 in the mountain ranges just north of Santa Barbara. On 
 March 10, 1933, 115 fatalities and $40 million damage re- 
 sulted from an earthquake that struck close to Long Beach. 
 This earthquake had a magnitude of only 6.3, but the zone 
 of greatest energy release seems to have been only a few miles 
 
 14 
 
away, in or near the Signal Hill area. On May 18, 1940, 
 an earthquake slightly stronger than the Long Beach shock 
 centered near Imperial in Imperial Valley, causing $6 million 
 damage and killing several residents. It was featured by a hori- 
 zontal fault movement of 15 feet. On June 30, 1941, another 
 shock near Santa Barbara resulted in $100,000 damage, and 
 on November 14 of the same year, the Torrance-Gardena area 
 of Los Angeles County suffered $1 million damage. On 
 November 17, 1949, a minor disturbance centering on Termi- 
 nal Island in San Pedro Bay sheared 200 oil wells near the 
 1,700-foot level, causing more than $9 million damage. In 
 1951, 1955, and 1961, earthquakes barely perceptible at the 
 surface caused additional subsurface damage ($3.0, $3.0, and 
 $4.5 million, respectively) to oil wells on Terminal Island and 
 adjacent mainland. On July 21, 1952, the strongest earthquake 
 to hit California since 1906 shook the area south of Bakers- 
 field. The main shock and the series of strong aftershocks 
 killed 14 people and caused an estimated $60 million damage to 
 buildings, railroads, and crops. It was caused by a slip along 
 the White Wolf fault, one of the more obscure faults, that 
 parallels the Oarlock fault about 20 miles northwest of the 
 latter. Hardest hit were Arvin and Tehachapi, although more 
 damage occurred in Bakersfield because of its greater size. 
 Bakersfield was badly shaken, not only by the principal shock, 
 but also by a strong aftershock that centered very close to the 
 city on August 22. It took two lives and caused an additional 
 $10 million in damage. On December 21, 1954, Eureka and 
 Areata were violently shaken and nearly every building sus- 
 tained structural damage. Damage was estimated at $2 million 
 in Eureka and $100,000 in Areata. A strong shock in October 
 1955 between Concord and Walnut Creek caused the death of 
 one person and $1 million damage. The San Francisco Bay 
 area earthquake in March 1957 caused landslides, broke win- 
 dows, and cracked highway pavements and a reinforced con- 
 crete water reservoir. Overall damage amounted to about $1 
 million. On April 8, 1961, a shock about 13 miles south of 
 HoUister on the San Andreas fault damaged several buildings, 
 knocked over chimneys, and ruptured a water line at Hollister. 
 
 15 
 
The June 27, I9665 Parkfield earthquake caused minor surface 
 faulting in a narrow zone along the San Andreas fault. Several 
 bridges in the area sustained minor damage and a highway 
 was cracked near Cholame. Minor, but extensive, ground 
 cracks resulted from a moderate earthquake northeast of 
 Truckee on September 12, 1966. Several bridges sustained 
 minor damage. Ground cracks appeared in the earth-dams at 
 Boca and Prosser, and chimneys fell in many towns. The strong- 
 est earthquake in 15 years centered in northeastern San Diego 
 County on April 9, 1968. Minor right-lateral displacement 
 occurred on Coyote fault. Highway 78 sustained cracks, land- 
 slides were noted, chimneys toppled, and walls cracked. The 
 magnitude 6.5 shock was felt over 60,000 square miles. 
 
 A swarm of eathquakes from July through December 1954 
 in the Stillwater and Clan Alpine Mountains near Fallon, Nev., 
 ranged from intensity VI through X and caused great surface 
 ruptures that damaged canals and drainage systems, irrigation 
 structures, and highways. Since the area was sparsely settled, 
 it experienced little property damage to homes and office build- 
 ings. Of particular interest was the 5 to 15 feet of vertical 
 movement in the Dixie Valley, and east of Fairview Peak 6 to 
 20 feet of vertical and 4 to 12 feet of horizontal movements. 
 
 The Puget Sound area has always been known to be mod- 
 erately seismic with a record of a few hard jolts at long inter- 
 vals, but an increase in activity during recent years was 
 climaxed by a strong shock on April 13, 1949. More than $25 
 million damage was sustained in cities bordering the Sound 
 and several were killed. A shock in February 1946 caused about 
 $250,000 damage in Seattle and several additional earthquakes 
 were only slightly less severe. The April 29, 1965, shock caused 
 several deaths in the area and an estimated property damage 
 of $12.5 million. 
 
 The greater violence and damage associated with earthquakes 
 in the Pacific coast and Rocky Mountain regions in comparison 
 to the East is generally attributed to their shallower foci 
 (depths). Most of the major rock fractures in California ap- 
 pear to be only 10 or 15 miles deep. In other areas of the 
 
 16 
 
country, this may be doubled or tripled, thereby causing less 
 violent motion at the surface. 
 
 Alaska. — The seismic history of Alaska is inadequately 
 known, even though earthquakes have been reported felt at 
 many Alaskan towns since the late 1 700's. Early reports were 
 based on observed effects and in a sparsely settled region they 
 are necessarily fragmentary. 
 
 Alaska is one of the important links in the great seismic belt 
 that circumscribes the Pacific. The principal earthquakes of 
 Alaska center in two seismic zones, both of which lie in the cir- 
 cum-Pacific belt. The most important of these, the Aleutian 
 arc, is approximately 2,000 miles in length and contains about 
 76 volcanoes, of which 36 have recorded activity since 1760. 
 This zone is a nearly classical island arc with shallow-focus 
 earthquakes associated with an oceanic foredeep and with 
 intermediate-depth earthquakes under and behind the vol- 
 canic islands. The second zone begins north of Yakutat Bay 
 and extends southeastward to the west coast of Vancouver 
 Island. 
 
 In September 1899, the Yakutat Bay area near the southwest 
 tip of the Canadian boundary experienced two of the notable 
 earthquakes of the last century. Both were over magnitude 8 
 on the Richter scale. The second shock raised the shoreline 
 over a considerable length, and at one point there was a verti- 
 cal fault slip of 49 feet — one of the greatest vertical fault move- 
 ments known. In July 1958, a major shock was felt as far south 
 as Seattle, Wash., and east to Whitehorse, Yukon Territory. 
 Three persons were killed on Khantaak Island in Yakutat Bay, 
 and a fishing boat with two persons disappeared after being 
 caught by a huge wave (about 1,740 feet in height) in Lituya 
 Bay. The Prince William Sound earthquake in March 1964, 
 one of the strongest ever recorded in North America, caused 
 severe property damage in Anchorage and coastal communi- 
 ties. The shock and tsunami killed 131 persons and caused 
 about $500 million property damage. At one point off Mon- 
 tague Island there was 42 to 50 feet of absolute vertical 
 displacement. 
 
 Hawaii. — Seismic activity in the islands centers on the Island 
 
 17 
 
of Hawaii, the largest, as well as the most easterly, in the group. 
 Hawaii is best known for the spectacular eruptions of Kilauea 
 volcano and the lava flows that frequently break from the 
 slopes of Mauna Loa. Mauna Loa is the largest active volcano 
 in the world and rises almost 30,000 feet from the ocean floor. 
 While there is an abundance of strong tremors directly as- 
 sociated with volcanic activity, some of the heavier shocks that 
 are at times felt over all the islands to as far as Honolulu seem 
 to be of tectonic origin. These epicenters trend generally in a 
 northeast-southwest direction and may originate onshore, or 
 beneath the sea. An earthquake in 1868 was extremely violent 
 and destructive considering the sparsely settled nature of the 
 island. Hilo, on the northeast coast, frequently suffers severe 
 earthquake damage. Strong submarine shocks off the south- 
 west coast occasionally cause considerable damage nearby, 
 while those to the north and east may be felt with nearly 
 equal violence on several islands. 
 
 Puerto Rico and Panama Canal Zone. — Puerto Rico is in 
 the loop or belt of seismic activity that extends eastward through 
 the West Indies from the Pacific. Many strong shocks in this 
 area have their origins in ocean deeps. A violent shock in the 
 deep off the northeastern coast of the Dominican Republic 
 caused widespread destruction in that country on August 4, 
 1946, and was strongly felt all over Puerto Rico. Violent shocks 
 have also originated near the islands just east of Puerto Rico. 
 The most notable disturbance in recent years was that of 
 October 11, 1918, originating in Mona Passage at the northwest 
 corner of the island. The resultant sea wave killed 116 persons 
 and caused widespread damage in Mayaguez and nearby towns. 
 Of the earlier shocks, that of 1867 was the strongest. While some 
 moderately strong shocks have originated on the island itself, 
 the greatest menace has been from those of submarine origin. 
 
 Strong earthquakes do not originate in the Panama Canal 
 Zone, nor in the portions of Panama immediately adjacent 
 to it, but these areas are occasionally shaken by earthquakes 
 centered in western Panama or northwestern Colombia. The 
 main seismic belt of the Pacific bypasses the Canal Zone to the 
 southwest, but submarine shocks from this area are sometimes 
 felt strongly in the Canal Zone. 
 
 18 
 
 I 
 
Tsunami Warning Service 
 
 One of the important services of the Coast and Geodetic 
 Survey is the maintenance of the tsunami warning program. 
 The principal objective is to minimize the hazards of tsunamis, 
 especially hazards to human life and health, by disseminating 
 warnings to the public through participating agencies. Al- 
 though relatively large distances are involved, there is time to 
 locate the earthquake, determine whether a sea wave has been 
 generated, and issue warnings to Pacific coastal populations 
 that might be endangered. 
 
 In Alaska, Arizona, Guam, Hawaii, and Washington, the 
 Survey operates visible-recording seismographs that ring alarms 
 whenever a shock of magnitude 6 J/2 or larger is being registered. 
 Ten additional seismograph stations in several countries partici- 
 pate in this operation. Observers at 39 tide stations scattered 
 throughout the Pacific immediately report unusual tidal dis- 
 turbances to the monitoring station near Honolulu. A high- 
 priority communications service is maintained between 
 reporting agencies through the combined facilities of the 
 Defense Communication Agency, Federal Aviation Administra- 
 tion, the National Aeronautics and Space Administration, and 
 other governmental and private agencies, domestic and foreign. 
 With the aid of these agencies, the Survey's monitoring station 
 near Honolulu is able to locate a submarine shock and verify 
 the existence of a tsunami within 2 or 3 hours. 
 
 A regional tsunami warning system has been developed in 
 Alaska with Palmer Observatory as headquarters. This system 
 is responsible for providing warnings to the coastal communi- 
 ties in Alaska of locally generated tsunamis. 
 
 Tsunamis. — ^A tsunami (seismic sea wave) is a series of 
 traveling waves of extremely long period and length, generated 
 by disturbances ajssociated with earthquakes near or below 
 the ocean floor. Submarine earthquakes occasionally generate 
 seismic sea waves that travel thousands of miles over the 
 oceans and cause great damage to shore property when they 
 either pile up and break, or simply flood shoreline areas. Many 
 ships have been carried ashore by such waves and thousands 
 of lives have been lost, particularly in South America and 
 
 19 
 
Japan. In the deep ocean, these waves cannot be felt aboard 
 ships and they cannot be seen from the air. Their length from 
 crest to crest may be a hundred miles or more, their height from 
 trough to crest only a few feet, and they may travel at 600 miles 
 per hour. It took the tsunami of 1960 about 15 hours to travel 
 from Chile, where the earthquake originated, to Hilo, Hawaii. 
 
 In April 1946, sea waves generated by a submarine earth- 
 quake in the Aleutian Islands caused $25 milhon damage in 
 the Hawaiian Islands. Hilo was hardest hit. The Scotch Cap 
 lighthouse, high on a cliff a few miles from the epicenter off 
 Unimak Island, Alaska, was washed away and its five occupants 
 drowned. 
 
 In March 1957, a magnitude 8.3 earthquake in the Aleutian 
 Islands generated disastrous sea waves that caused about $3 
 million property damage in Hawaii, and lighter damage on 
 the west coast of the United States, in Chile and Japan. A 40- 
 foot wave surged into the area where the Scotch Cap lighthouse 
 was washed away in 1946. The major tremor was accompanied 
 by a swarm of more than 300 aftershocks, of which 14 had 
 magnitudes above 6%. 
 
 The tsunami which originated oflF the coast of Chile in May 
 1960 devastated the adjacent coastline and caused heavy loss 
 to both life and property. In Hilo, Hawaii, 61 lives were lost and 
 about $25 million damage was sustained, although 6 hours of 
 advance warning was given by the Coast and Geodetic Sur- 
 vey's Seismic Sea Wave Warning System (now the Tsunami 
 Warning System) . In Chile the earthquake and tsunami caused 
 more than 2,000 deaths and $550 miUion property damage. 
 About $50 million property damage occurred in Japan where 
 138 residents were dead or missing; 32 died in the Philippines; 
 and about $500,000 property damage was sustained along the 
 west coast of the United States. Unusually large waves were also 
 reported on other Pacific islands. 
 
 In March 1964 an earthquake of magnitude 8.5 near An- 
 chorage, Alaska, generated destructive sea waves on the shores 
 bordering the Gulf of Alaska and inflicted heavy property 
 damage to Seward, Kodiak, Cordova, Whittier, Homer, and 
 other communities. Tsunami damage was also sustained along 
 
 20 
 
 ( 
 
the Canadian coast, the west coast of the United States, and in 
 Hawaii. Seiche action in rivers and coastal waterways was 
 observed on the gulf coast of the United States. Communities 
 on the Gulf of Alaska sustained 107 fatalities as result of the 
 tsunami; 11 died at Crescent City, Calif.; and four were 
 drowned at Newport, Oreg. Nine persons died in Anchorage as 
 direct result of the earthquake. 
 
 What To Do During an Earthquake 
 
 When a destructive earthquake centers in or near a popu- 
 lated area the results can be catastrophic. It may flatten build- 
 ings, collapse dams and bridges, sever communications, cause 
 landslides, and leave gaping cracks in the ground. And it 
 sometimes generates damaging tsunamis (seismic sea waves) 
 that inundate and demolish Pacific coastal areas thousands 
 of miles from its epicenter. 
 
 Since property damage as result of strong earthquakes will 
 never be completely eliminated, the most important defensive 
 actions that can be taken to minimize damage, injury, and 
 loss of life are : 
 
 1 . Learn about earthquakes, their possible effects, and where 
 they are most likely to occur. 
 
 2. Use "earthquake-resistant design" in construction. 
 
 3. Construct your home on solid ground, not on made land 
 or alluvial fill. 
 
 4. Know "what to do" should an earthquake occur in your 
 city. 
 
 Since this country was settled, about 1,500 persons have 
 died during earthquakes (or earthquake-generated tsunamis 
 and fires), and almost half this number resulted from the 1906 
 disaster in San Francisco, Calif. In comparison, Shenshi, China, 
 experienced an earthquake in 1556 that caused a reported 
 830,000 fatalities. Moderate shocks in foreign areas often cause 
 tremendous loss of life and property because of the weak con- 
 struction and density of population. 
 
 335-a4^ O— 6)9 4 2 1 
 
Even though earthquakes can occur anywhere at any time, 
 the chance of experiencing a damaging shock in the United 
 States is probably greater in California or Alaska. If you live 
 in these States, or in any seismic region where alluvium and 
 soft soils are prevalent, the risk of strong shaking during a 
 nearby earthquake is particularly high. Loose, watercharged 
 natural ground is also dangerous to structures. Past earthquakes 
 have taught that the safest ground for construction is solid rock. 
 
 What should you do then to prevent injury and loss of life 
 when the earth shakes beneath your feet and your house begins 
 to shake and sway? 
 
 Keep calm. Do not panic or run into the street. Many of 
 the deaths and injuries recorded during earthquakes have oc- 
 curred when frightened residents ran into the streets just as 
 walls and chimneys were collapsing and cornices and other 
 objects were falling. 
 
 If you are indoors, take cover immediately, under a table, 
 desk, or any object that will protect you against a falling ceiUng; 
 or stand against an inside wall (preferably a basement wall with 
 bearing strength ) or under a doorway. 
 
 If you are outside on a sidewalk, get off it as quickly as possi- 
 ble, preferably into an open doorway or into the middle of the 
 street if it is a wide one. Stay clear of utility poles, cornices of 
 buildings, or other objects that might fall on you. 
 
 If you are outside in the open flat country, you are probably 
 in the safest place to experience a strong earthquake. Ground 
 cracks might occur, but the chance of being "swallowed" by 
 such a fissure is extremely slight. Shock waves can also uproot 
 trees, or snap their tops off, and generate massive landslides. 
 They may occur in areas of unconsolidated ground on steep 
 slopes, and especially along the sea coast. In the 1964 Alaska 
 shock the Turnagain Heights area of Anchorage was literally 
 destroyed by landslide and slumping action. 
 
 If you are driving a car, pull to the center of the street away 
 from tall structures and stop until the earthquake has sub- 
 sided. Remain in your automobile. It provides protection that 
 you will not have on the outside. 
 
 22 
 
If you are located on the Pacific coast within a mile of the 
 ocean and less than 100 feet above sea level, there exists an 
 additional danger — the possible generation of a seismic sea 
 wave. Do not stay in a low-lying coastal area after a strong 
 local earthquake. Approaching tsunamis are sometimes 
 preceded by a noticeable rise or fall of coastal water. This is 
 nature's tsunami warning and should be heeded. A local 
 tsunami warning system now exists in Alaska to warn coastal 
 communities of this danger, and the ESSA Honolulu Observa- 
 tory issues warnings for tsunamis of distant origin. Stay tuned 
 to your radio or television during a tsunami emergency. Bul- 
 letins issued by the Civil Defense and local authorities may 
 save your life. 
 
 AFTER THE EARTHQUAKE. . . 
 
 Probably the most disheartening feature in the aftermath of 
 a damaging earthquake is the repeated occurrence of after- 
 shocks. Remember that aftershocks normally follow all large 
 earthquakes, but almost always with decreasing frequency 
 and violence. It is very rare for one to reach the intensity of the 
 main shock, although it has happened on a few occasions (no- 
 tably the Missouri shocks of December 1811 and January and 
 February 1812; all three were intensity XII, and probably of 
 Richter magnitude 8 or greater). Aftershocks may continue 
 for a day or two, or in some cases for weeks or months following 
 the principal shock. They generally center at various points 
 in the epicentral area, sometimes 15 miles or more from the 
 source of the main shock. 
 
 Therefore^ do not reoccupy a seriously damaged building 
 or home without the approval of local authorities. It may have 
 been weakened to the point that a sharp aftershock could cause 
 it to collapse. 
 
 Stay away from fallen or dangling electric wires. Report them 
 to responsible officials. 
 
 Be careful with cigarettes or open fires of any kind, because 
 there may be leaking gas lines in your house or nearby. Strong 
 earthquakes often break underground pipes. 
 
 23 
 
Stay clear of areas of extensive earthquake damage. If you 
 are not qualified to give assistance you will only hamper first 
 aid and rescue work. 
 
 Do not drive unless necessary. If you must, drive with ex- 
 treme caution. Watch for damaged streets, landslides, or other 
 hazards to pedestrians and drivers, and report them to local 
 authorities. 
 
 Do not pass on rumors or exaggerated reports. This will often 
 cause more confusion and panic. 
 
 If needed, get food and shelter, medical care and clothing 
 at Red Cross stations. Local authorities will guide you to these 
 locations. 
 
 Follow the advice and instructions of local authorities on 
 ways to assist you, your family, and your neighbors to recover 
 from the disaster and eliminate further injury or loss of life. 
 
 Nature of Earthquakes and Seismic Waves 
 
 Strong earthquakes are usually due to the rupturing of great 
 masses of rock many miles beneath the surface of the earth. 
 This generally takes the form of slipping or sliding along a 
 rupture plane called a fault. Rocks on opposite sides of the 
 fault slide past each other in response to a strained condition, 
 moving at any angle that will produce a position of rest. It is 
 this snapping back of overstressed and deformed rocks, follow- 
 ing fracture, that causes earthquakes. 
 
 The repeated occurrence of earthquakes along the same 
 fault over a long period of years is not unusual. Judging from 
 the ground displacements observed after large earthquakes, these 
 fault slips may be as much as 50 feet. In some seismic areas, 
 Japan for example, geodetic surveys often show that great 
 blocks of rock, tens of miles in dimension, undergo tilting in 
 many earthquakes. The ultimate cause of this continual adjust- 
 ment of crustal rock is thought to be due to a relentless flowing 
 or creeping of underlying ultrabasic rock. These rocks behave as 
 plastic material which, like a mass of paraffin, will change shape 
 without fracture if the distorting forces are applied slowly and 
 
 24 
 
steadily, but will crack if applied too quickly. The cause of rock 
 creep is largely a matter of conjecture. It could be due to cooling 
 of the earth, convection currents set up by radioactivity in the 
 deeper rocks, changing loads on the surface due to the transfer 
 of material through erosion and deposition, or other causes. 
 
 The great majority of so-called shallow earthquakes origi- 
 nate at depths of 10 to 20 miles; however, they may occur at 
 any depth down to a maximum of 450 miles. Earthquakes due 
 to volcanic activity may seem violent locally, but compared 
 to tectonic earthquakes that are frequently registered on in- 
 struments all over the world, they are very superficial and 
 felt over small distances. 
 
 Earthquakes cannot be predicted with respect to time and 
 place of occurrence except in terms that have little or no mean- 
 ing. When the seismic history of an area is studied, the pattern 
 of earthquake occurrence is found to be so complex and erratic 
 that it is impossible to derive from the data a formula to predict 
 future disturbances. The gravitational pull of the planets is 
 apparently insufficient to cause earthquakes, and it has not been 
 demonstrated that such stresses are sufficient to serve regularly 
 as trigger forces in "setting off" earthquakes that are just about 
 ready to occur. 
 
 In some areas, large sections of terrain move slowly, along 
 with the creep or flow of the deep basement rock, and when 
 the pattern of this movement shows that some sections of the 
 rock are "stuck" and obviously building up stresses that will 
 eventually cause fracture, it is clear that the stage is set for an 
 earthquake. Such a condition exists along the San Andreas fault 
 in California where precise geodetic surveys have shown the 
 terrain on one side of the fault has moved about 20 feet rela- 
 tive to the terrain on the other side since 1906. One must assume 
 that, sooner or later, the stresses building up in between will 
 again fracture the rocks along the fault ; that the crustal rocks 
 and overlying terrain will again slide along the fault or surface 
 of fracture ; and that in a matter of seconds, a new state of stress 
 equilibrium in the rock will be established. One might logically 
 predict earthquakes in such areas, but the time of occurrence 
 will always be in doubt until the complete histories of a number 
 of earthquake cycles are thoroughly known. 
 
 25 
 
A magnetometer array, established on the San Andreas fault 
 in 1965 by Stanford University, revealed small changes in the 
 geomagnetic field on five occasions between December 1965 
 and October 1966. In each case the changes were followed by 
 creep, or slight dislocation of the fault, and occasionally by 
 earthquakes. These changes in the earth's magnetic field and 
 their possible connection with earthquake prediction prompted 
 a denser magnetometer array to be established south of HoUister 
 in late 1966. On April 18, 1967, a local decrease in the magnetic 
 field was observed simultaneously on four instruments posi- 
 tioned over a 25-km span along the San Andreas fault. Creep 
 displacement of 4 millimeters occurred 16 hours later, and a 
 series of local earthquakes, the largest not exceeding Richter 
 magnitude 3.6, followed April 20-22, 1967. An explanation 
 by a Stanford scientist suggested the magnetic changes were 
 caused by stresses some 6 to 12 miles below the earth's surface. 
 A slipping motion along the fault possibly begins at depths 
 where the rock is soft without causing tremors. Earthquakes 
 may then follow due to stresses imposed on rocks at more 
 shallow depths. 
 
 Magnetic disturbances were also reported 1 hour and 4 
 minutes before the occurrence of the great Alaskan earthquake 
 of March 1964. Monitoring magnetic changes may therefore 
 be a means of earthquake prediction in the future. 
 
 In Japan, some successful predictions of strong aftershocks 
 have been made through the discovery that certain changes in 
 terrain and certain earthquake sequences form a pattern that 
 seems to repeat itself after each great shock in the area under 
 study. 
 
 When great masses of rock are fractured, violent vibrations 
 are radiated in all directions through the rock and overlying 
 soil. It is the force of these vibrations that damages structures 
 and frightens residents in earthquake areas. On the lighter 
 geological formations that overlie the ruptured basement rocks, 
 the force of the vibrations may be magnified 5-, 10-, or 20-fold, 
 increasing in severity with the lightness of the rock or soil and 
 the height of the local water table. This accounts in part for 
 the lack of uniformity in the damage sustained in a community 
 
 26 
 
as result of an earthquake, but much also depends upon the 
 sturdiness of individual buildings. 
 
 In strong earthquakes, these seismic vibrations, or waves, 
 penetrate the entire structure of the earth and travel all over 
 its surface. While such shocks are seldom felt farther than a 
 thousand miles from their source, sensitive seismographs have 
 registered these unfelt vibrations in all parts of the world for 
 more than 50 years. Such seismic waves are extremely com- 
 plex, but a few basic facts will serve to explain how they are 
 propagated through the earth (see fig. 3 ) and how the distance 
 to an earthquake can be determined from a seismograph record. 
 
 Figure 3. — Earthquake waves recorded on typical seismogram and paths 
 of propagation through the earth. 
 
 27 
 
Two types of waves travel at different speeds through the 
 earth's interior. They are known as interior waves. The faster 
 one — the P wave — alternately compresses and dilates the rock 
 as it travels forward; the slower one — the S wave — ^shakes the 
 rock sideways as it advances, not unlike the vibration of a 
 violin string. Seismological tables based on many thousands 
 of seismograph readings show to the nearest second the time 
 it takes each of these wave groups to travel to points on the 
 earth's surface at various great circle distances from an earth- 
 quake origin (see fig. 4). Therefore, the difference in the ar- 
 rival times of two such wave groups at a seismograph station 
 corresponds to some particular epicentral distance given in 
 the seismological tables. These two waves are usually well de- 
 fined on seismograph records, and anyone who can recognize 
 them can obtain the corresponding epicentral distance from 
 the seismological tables. The largest waves recorded at distant 
 stations, however, are usually waves that travel at nearly uni- 
 form speed along the surface of the earth only and are known 
 as surface (L) waves. 
 
 Besides registering earthquake vibrations, seismographs may 
 also record ground vibrations from quarry blasts and other 
 violent explosions. The distance at which such a disturbance 
 may be recorded depends upon the strength of the blast, the 
 distance to the recording station, and the amplifying power of 
 
 ^ 3000 
 
 TRAVEL-TIME CURVES 
 
 TIME IN MINUTES 
 Figure 4. — Travel-time curves with idealized seismograms superimposed. 
 
 28 
 
the seismograph. Although records of blasts and local earth- 
 quakes are frequently recorded, the average instrument does 
 not furnish a good record of the high-frequency waves gen- 
 erated and interpretation is consequently difficult. The difficulty 
 can be overcome by choosing a seismograph of a tyj>e that will 
 give satisfactory recordings of high-frequency waves. 
 
 Until recently, all earthquake epicenters were located on 
 large terrestrial globes by swinging arcs around several observa- 
 tory locations, using as radii the epicentral distances deter- 
 mined from the station records (see fig. 5). This method is 
 still utilized for fast, on-the-spot locations of earthquakes of 
 unusual interest, but for more precise locations, modem elec- 
 tronic computer techniques are used. The computer pemiits 
 the determination of many more earthquake locations in an 
 equivalent amount of time. The epicenter determination pro- 
 gram is conducted at the Coast Survey's National Earthquake 
 Information Center established in August 1966 and described 
 in an earlier section of this report. 
 
 Figure 5. — Geophysicists of the National Earthquake Information Center 
 illustrating technique of locating an earthquake on a 3 2 -inch globe. 
 
 29 
 
Seismographs 
 
 Seismographs, basically, are nothing more than carefully 
 constructed pendulums. When the ground vibrates the instru- 
 ment, the pendulum mass tends to remain immovable so that 
 a measurable differential motion results. Many seismograph 
 pendulums take 10 or even 20 seconds to make a complete 
 swing. The reason for this is that most waves from distant 
 earthquakes have long periods and long wavelengths, and it 
 requires a long-period pendulum to obtain a measurable dif- 
 ference between the moving pendulum and the moving ground. 
 In nearby earthquakes, however, the ground vibrations are 
 of short period, and almost any simple short-period pendulum 
 would suffice. A long period can be obtained by swinging the 
 pendulum in a nearly horizontal plane about a nearly upright 
 post, like a gate or door that is slightly tilted. It always takes a 
 steady position in the direction in which the hinges are tilted. 
 These are called horizontal pendulums. It requires two such 
 pendulums, and another that measures vertical motion to obtain 
 the complete motion of the ground at a seismograph station. 
 
 The second important requirement of a seismograph pendu- 
 lum is that it must be damped to prevent swinging mostly in 
 its own free period and obscuring other shorter and longer pe- 
 riods that are present in the ground motion. Some seismographs 
 are damped with oil; i.e., a vane or paddle fixed rigidly to the 
 pendulum mass moves to and fro in a container full of oil 
 whenever the pendulum moves, relative to the earth. If such a 
 pendulum is pulled to one side 1 inch and released, and it then 
 overshoots the original position of rest by 0.1 inch, the dampn 
 ing ratio is 10 to 1 which is about proper. Such a pendulum will 
 give a good record of the ground motion. The great majority 
 of modem seismographs (see fig. 6), however, are not damped 
 with oil. Instead, a metal plate that passes closely between 
 the poles of a powerful magnet fixed to the instrument frame is 
 used. 
 
 The third requirement of a seismograph pendulum is that its 
 motion, relative to the ground, must usually be magnified many 
 times by a mechanical lever system, optical levers, or electrical 
 
 30 
 
jJk Q, |J| b 
 w^ ^1^ ^^ 
 
 Figure 6. — Modern seismograph system as used in the Network of 
 Standard Seismograph Stations. 
 
 methods. Mechanical lever systems that magnify the pendulum 
 motion from 10 to several hundred times are used on most 
 older-type seismographs. In principle, such a lever rotates 
 horizontally on a pivoted, vertical spindle, set in jewel bearings 
 fixed to the instrument frame. The short end is connected to the 
 pendulum mass, while the long end, which rotates through a 
 much greater distance, carries a delicately mounted steel pin or 
 stylus that scratches a fine line on a sheet of smoked paper 
 moving beneath it. In making records of this kind, a strip of 
 paper about a yard long and 6 inches wide is wound around 
 a drum, then covered with a fine smoke film over a "sooty" 
 flame and the drum set back on the seismograph recording 
 mechanism. The drum usually turns through one revolution 
 an hour, and at the same time moves sideways in a spiral so 
 that 24 lines can be scratched on the paper without the lines 
 overlapping. When an earthquake vibrates the ground beneath 
 the stationary pendulum a wavy line is scratched on the paper. 
 
 31 
 
This is the seismograph record and on it can be seen the princi- 
 pal seismic wave groups explained in the preceding section. 
 Figure 7 shows a visible-recording seismograph; figure 8 dis- 
 plays a tracing of a typical record. 
 
 Greater magnification is obtained by dispensing with cum- 
 bersome mechanical levers and smoked paper and using beams 
 of light that write fine lines on a sheet of photographic paper. 
 This requires operating the seismographs in dark rooms, now 
 a part of many seismological stations. Such instruments are 
 designed so that a mirror in the pendulum system rotates with 
 the pendulum; consequently, when a fixed beam of light is 
 reflected from the mirror onto the photographic recording 
 paper, it traces a wavy line during an earthquake just like the 
 record made by the smoked paper recorder (see fig. 8). Most 
 seismographs using such systems magnify the pendulum motion 
 one or two thousand times. 
 
 Figure 7. — An assembly for visible-recording seismograph. A — control 
 
 box. B — galvanometer and recording pen. C — revolving drum that 
 
 registers all movements of writing pen. 
 
 32 
 
The greatest magnifications are ordinarily obtained with 
 electromagnetic seismographs. In most of these, a coil made of 
 many turns of fine wire is fixed to the seismograph pendulum 
 and forced by the earthquake motion to oscillate between the 
 poles of powerful magnets connected to the instrument frame. 
 The current thus generated is sent through a sensitive galvanom- 
 eter that makes a continuous record on photographic paper, a 
 mirrior, or hot stylus. With such instruments the ground motion 
 can be magnified several hundred thousand times. 
 
 Special seismographs that record destructive earthquake 
 motions usually have very short-period pendulums. In fact, 
 they are more like weighted springs. They record the accelera- 
 tion, or force, of the motion on photographic paper. Instead 
 of operating continuously like regular seismographs, they re- 
 main inoperative until a strong earthquake starts them. A 
 starting pendulum closes an electrical circuit that causes the 
 entire recording mechanism to operate for about 1 J/2 minutes 
 (see fig. 9). 
 
 Seismographs do not record the motion of the ground di- 
 rectly. The relationship between the actual ground movement 
 and the movements shown on a seismograph record is very 
 complex and will not be discussed here. It will suffice to say 
 that when a seismograph is properly calibrated, the seismol- 
 ogist knows how much his instrument will magnify ground 
 waves ot all periods. This depends primarily on the pendulum 
 
 Figure 8. — College, Alaska, seismogram showing recording of earthquake 
 on February 22, 1958, in Aleutian Islands. 
 
 33 
 
Figure 9. — Coast and Geodetic Survey accelerograph. 
 
 period, the period of waves in the earth beneath, and a number 
 of other factors, and explains why records of the same ground 
 motion made with various types of instruments are so different. 
 Most important to the seismograph station director is the matter 
 of keeping his time controls accurate to a fraction of a second. 
 Earthquake waves pass the station at speeds as high as 5, 10, and 
 15 miles per second ; to determine earthquake distances from the 
 arrival times of various wave groups, he must therefore be 
 diligent with regard to time accuracy. 
 
 In the United States, about 250 seismograph stations are in 
 continuous operation (see table 1). Throughout the world 
 there are approximately 900 stations. The Network of Stand- 
 ard Seismographs, which was initiated in 1961, now has 115 
 operating stations. The records from this network are submitted 
 to the Data Center in Asheville, N.C., where permanent file 
 copies are made. At present, the Data Center is reproducing 
 over 100,000 copies of seismograms per month to fill requests 
 of seismologists throughout the world. 
 
 34 
 
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 35 
 
Descriptive Reports on Earthquakes 
 
 One of the important functions of the Coast and Geodetic 
 Survey is to collect descriptive information on earthquakes that 
 occur in the United States. The information is obtained from 
 questionnaires sent to volunteer observers immediately after 
 any felt earthquake, from field investigations after destructive 
 earthquakes, and from the news media. These historic earth- 
 quake descriptions are published quarterly in Abstracts of 
 Earthquake Reports for the United States and summarized 
 annually in United States Earthquakes. 
 
 These publications not only present detailed information on 
 earthquakes, but they also summarize information on stronger 
 earthquakes in the concise form of intensity distribution maps. 
 A typical map is shown in figure 10. For this purpose, intensity 
 is defined as the apparent violence of an earthquake at any loca- 
 tion as determined from a scale based on observed effects. At 
 any given distance from the epicenter, intensity depends on 
 the strength of the earthquake at the focus, the depth of focus, 
 local geological factors, and in populated areas, on the type 
 and quality of construction. 
 
 In this country, the Modified Mercalli Intensity Scale of 
 193P is used to evaluate earthquake intensity. In abridged 
 form, criteria for this scale are : 
 
 I. Not felt except by a very few under specially favorable 
 
 circumstances. (I Rossi-Forel Scale) 
 II. Felt only by a few persons at rest, especially on upper 
 floors of buildings. Delicately suspended objects may 
 swing. (I to II Rossi-Forel Scale) 
 III. Felt quite noticeably indoors, especially on upper floors 
 of buildings, but many people do not recognize it as an 
 earthquake. Standing motorcars may rock slightly. Vi- 
 bration like passing of truck. Duration estimated. (Ill 
 Rossi-Forel Scale) 
 
 ^ Harry O. Wood and Frank Neumann^ in Bulletin of the Seismological 
 Society of America, vol. 21, No. 4, December 1931. 
 
 36 
 
IV. During the day, felt indoors by many, outdoors by few. 
 At night, some awakened. Dishes, windows, doors dis- 
 turbed; walls make creaking sound. Sensation like heavy 
 truck striking building. Standing motorcars rocked 
 noticeably. (IV to V Rossi-Forel Scale) 
 V. Felt by nearly everyone, many awakened. Some dishes, 
 windows, etc., broken; a few instances of cracked plas- 
 ter; unstable objects overturned. Disturbances of trees, 
 poles, and other tall objects sometimes noticed. Pen- 
 dulum clocks may stop. (V to VI Rossi-Forel Scale) 
 
 VI. Felt by all, many frightened and run outdoors. Some 
 heavy furniture moved ; a few instances of fallen plaster 
 or damaged chimneys. Damage slight. (VI to VII Rossi- 
 Forel Scale) 
 VII. Everybody runs outdoors. Damage negligible in build- 
 ings of good design and construction; slight to moderate 
 in well-built ordinary structures; considerable in poorly 
 built or badly designed structures; some chimneys bro- 
 ken. Noticed by persons driving motorcars. (VIII Rossi- 
 Forel Scale) 
 VIII. Damage slight in specially designed structures; consider- 
 able in ordinary, substantial buildings, with partial col- 
 lapse ; great in poorly built structures. Panel walls thrown 
 out of frame structures. Fall of chimneys, factory stacks, 
 columns, monuments, walls. Heavy furniture over- 
 turned. Sand and mud ejected in small amounts. 
 Changes in well water. Persons driving motorcars dis- 
 turbed. (VIII + to IX- Rossi-Forel Scale) 
 
 IX. Damage considerable in specially designed structures; 
 well-designed frame structures thrown out of plumb; 
 great in substantial buildings, with partial collapse. 
 Buildings shifted off foundations. Ground cracked con- 
 spicuously. Underground pipes broken. (IX+ Rossi- 
 Forel Scale) 
 X. Some well-built wooden structures destroyed; most 
 masonry and frame structures destroyed with their foun- 
 dations; ground badly cracked. Rails bent. Landslides 
 considerable from river banks and steep slopes. Shifted 
 sand and mud. Water splashed (slopped) over banks. 
 (X Rossi-Forel Scale) 
 
 37 
 
XL Few, if any, (masonry) structures remain standing. 
 Bridges destroyed. Broad fissures in ground. Under- 
 ground pipelines completely out of service. Earth slumps 
 and land slips in soft ground. Rails bent greatly. 
 XII. Damage totaL Waves seen on ground surfaces. Lines of 
 sight and level distorted. Objects thrown upward into 
 air. 
 
 Earthquake intensity is frequently confused with another 
 measure of earthquakes called magnitude. As indicated by the 
 preceding intensity scale, intensity is a measure of effects ob- 
 served by people in any part of the shaken area during an 
 earthquake. Magnitude, on the other hand, is a measure of 
 earthquake size observed on seismograph records, and relates 
 to the total seismic energy released by an earthquake. For any 
 earthquake there are many intensities, but only one magnitude. 
 An earthquake magnitude is usually reported first since it 
 is quickly determined from the measured amplitudes on seismo- 
 grams. On the magnitude scale the size of an earthquake is 
 defined as the logarithm of amplitude. Thus, each whole num- 
 ber step-up in magnitude represents a 10-fold increase in 
 earthquake size. 
 
 Engineering Seismology 
 
 All parts of the Survey's seismology program have engineer- 
 ing application to some degree. Location of epicenters provides 
 knowledge of seismicity. Descriptive reports provide knowledge 
 of earthquake effects. However, the phase of the program most 
 closely associated with engineering and usually thought of as 
 engineering seismology is the measurement, and subsequent 
 analysis, of strong and damaging motion during earthquakes. 
 
 To make such measurements the Survey maintains a net- 
 work of specially designed strong-motion recording seismo- 
 graphs with the cooperation of other agencies, universities, 
 engineers, and building owners. At the end of 1968 the network 
 included 262 instruments and extended from Alaska to South 
 America. Most of the instruments in the network record motion 
 in terms of acceleration, but at a number of stations, transient 
 displacements are also recorded. A typical acceleration record 
 is shown in figure 1 1 . 
 
 38 
 
r^ 
 
 
 VD 
 
 1— 
 
 0^ 
 
 (?) 
 
 ""^ 
 
 Q_ 
 
 o 
 
 00 
 
 
 O 
 
 
 lO 
 
 CI) 
 
 
 o 
 
 kO 
 
 F 
 
 o 
 
 CD 
 
 ^ 
 
 o 
 
 o 
 
 CD 
 
 o 
 
 CO 
 
 VD 
 
 
 
 o 
 
 ro 
 
 V 
 
 O 
 
 Qfl 
 
 ^•^ 
 
 
 c 
 
 > 
 
 1 
 
 a 
 E 
 
 ±1 
 
 r 
 
 0) 
 
 ro 
 
 <i) 
 
 tl. 
 
 Q 
 
 C/5 
 
 X o 
 
 ^ 0) 
 
 o 
 
 CD 
 
 CiO 
 
 39 
 
Unlike sensitive seismographs that operate 24 hours a day 
 and record distant earthquakes, strong-motion seismographs 
 remain idle until triggered into operation by local earth motion. 
 In a sense, the instruments freeze strong motion during an 
 earthquake for later use. At any convenient time after an earth- 
 quake the records can be converted to mechanical, electrical, or 
 numerical form. Thus unfrozen, the earthquake motion can be 
 repeated and used to determine the response of structures to 
 the earthquake. Acceleration records are the most useful. In 
 addition to determining structural response, they can be used, 
 through a mathematical process called integration, to calculate 
 earthquake motion in terms of velocity and displacement. The 
 calculated response spectra (curves) provide information on 
 how the damping and natural period of structures modify 
 earthquake effects. 
 
 Within the past few years, strong-motion seismographs in 
 Alaska and California have been supplemented by 376 rela- 
 tively low-cost instruments of the type shown in figure 12, and 
 this trend is expected to continue throughout the network. These 
 instruments, called seismoscopes, produce records of the type 
 shown in figure 13. The purpose of a seismoscope is to measure 
 directly one point on a response spectrum curve and to provide 
 additional information on the directional aspects of earthquake 
 motion. Being standardized, they allow comparison of surface 
 motion on various soils and rock in the vicinity of strong-motion 
 stations during an earthquake. 
 
 Since it is clear that the natural periods and damping of 
 buildings and other structures play an important role in de- 
 termining response, and thus stresses, during earthquakes, it is 
 necessary to measure the natural periods and damping of many 
 structures. To obtain this information the Survey has made 
 vibration measurements on more than 1,000 buildings and 
 other structures in the Pacific Coast and western Mountain 
 regions. The usual practice is to set up portable vibration meters 
 near the top of structures and to record briefly the vibrations 
 generated by wind and traffic. For more precise measurements 
 in determining damping as well as period, larger-amplitude 
 vibrations are generated by shaking machines temporarily in- 
 
 40 
 
Figure 12. — Coast and Geodetic Survey seismoscope. 
 
 Stalled in structures, and a number of vibration meters are used 
 to record motion. 
 
 Engineering seismological research to date reveals certain 
 factual information that should be of interest to everyone con- 
 cerned with the earthquake menace. To mitigate damage, and 
 possibly prevent injury and loss of life, the following factors 
 must be considered. Soft ground, and especially fill, is suscepti- 
 ble to greater intensity of motion than rock outcrops in the 
 same area. Obviously, special caution must be exercised in 
 building structures on soft ground. Even more caution must 
 be taken for a structure to be located partly on rock and partly 
 on softer ground, for the differential motion between the two 
 types of ground during an earthquake could wrench and 
 damage a structure almost as much as if the structure had been 
 located across an active fault. 
 
 41 
 
mx^i^^m^m^sms^msm.^ 
 
 ■i\ 
 
 I 
 
 1% 
 
 ^ 
 
 
 %. 
 
 
 
 
 "'' > 
 
 
 ^^. 
 
 s 
 
 ■s 
 
 ^zs-Ck- 
 
 Figure 13. — Seismoscope record produced by the instrument in fig. 12. 
 Record was written during the Parkfield, Calif., earthquake in June 1966. 
 
 A great percentage of damage and loss of life is undoubtedly 
 caused by poor judgment in use of building materials. Unrein- 
 forced brick or stone walls, poorly mortared and topped by 
 heavy roofs, for example, have caused thousands of deaths 
 during earthquakes. However, the same materials, when ade- 
 quately reinforced and tied together as a unit, make reasonably 
 earthquake-resistant structures. 
 
 The geometric shape of buildings is also important. A simple 
 rectangular shape is perhaps the best, but even for this shape, 
 the possibility of hammering between buildings must be con- 
 sidered since it is unlikely that two buildings or parts of 
 irregular buildings will vibrate in unison under seismic forces. 
 
 42 
 
Microseisms 
 
 The land surfaces of the world are no more in a state of 
 absolute quiet than the water surfaces. Minute waves, called 
 microseisms, are continuously moving through the rocks over 
 the entire surface of the earth. This is evident when examining 
 a sensitive seismograph record obtained in any part of the 
 world. The most prominent and important waves have periods 
 from about 4 to 7 seconds. In amplitude they range from ap- 
 proximately 0.00004 inch to 0.001 inch. There are others of 
 much shorter period and smaller amplitude and more localized 
 character. These waves are all called microseisms (see fig. 14) . 
 
 Microseismic waves are of meteorological origin just the 
 same as ocean waves; in fact, ocean waves may play an im- 
 portant part in their generation. Regardless of the mechanism 
 of their origin, it is a fact that storms and low-pressure areas at 
 sea are always accompanied by great increases in the amplitudes 
 of microseismic waves recorded at seismographic stations in the 
 surrounding coastal areas. In the West Indies microseisms have 
 been recorded from hurricanes as far as 2,000 miles from the 
 recording station. 
 
 U — 2 Min. — J ^ ^ ^ 
 
 Figure 14. — Seismogram showing microseismic storm in December 1956 
 at Sitka, Alaska. 
 
 43 
 
Cold wave fronts and other forms of meteorological changes 
 cause various unique types of microseismic disturbances that 
 have been the subject of much interest and investigation among 
 seismologists. The basic concepts that will satisfactorily explain 
 the generation and propagation of microseismic waves are yet 
 to be advanced. 
 
 44 
 
APPENDIX 
 
 Table 1 . — Active teleseismic stations of the United States 
 
 COAST AND GEODETIC SURVEY AND COOPERATING STATIONS- 
 
 Adak, Alaska 
 
 Coast and Geodetic Survey. 
 
 Albuquerque, N. Mex 
 
 Do. 
 
 Baker, Oreg 
 
 Do. 
 
 Barrow, Alaska 
 
 Do. 
 
 Biorka, Alaska 
 
 Do. 
 
 Boulder City, Nev 
 
 Bureau of Reclamation. 
 
 Butte, Mont 
 
 Montana School of Mines. 
 
 Byrd, Antarctica 
 
 Coast and Geodetic Survey. 
 
 Castle Rock, Calif 
 
 Earthquake Mechanisms Laboratory 
 (ESSA). 
 Do. 
 
 Chamberlain, Calif 
 
 College, Alaska (2) 
 
 Coast and Geodetic Survey. 
 
 Columbia, S.C 
 
 University of South Carolina. 
 
 Eureka, Nev 
 
 Eureka Corporation, Ltd. 
 
 Fayetteville, Ark.i 
 
 University of Arkansas. 
 
 Flaming Gorge, Utah 
 
 Bureau of Reclamation. 
 
 Gilmore Creek, Alaska . 
 
 Coast and Geodetic Survey. 
 
 Glen Canyon, Ariz 
 
 Bureau of Reclamation. 
 
 Guam, Mariana Islands 
 
 Coast and Geodetic Survey. 
 
 Holy Cross, Calif 
 
 Earthquake Mechanisms Laboratory 
 
 (ESSA). 
 Coast and Geodetic Survey. 
 Bureau of Reclamation. 
 
 Honolulu, Hawaii (4) 
 
 Hungry Horse, Mont 
 
 Kipapa, Hawaii 
 
 Coast and Geodetic Survey. 
 
 Kodiak, Alaska 
 
 Do. 
 
 Las Vegas, Nev 
 
 Do. 
 
 McMinnville, Tenn 
 
 Do. 
 
 Middleton Island, Alaska 
 
 Do. 
 
 Mt. Diablo, Calif 
 
 Earthquake Mechanisms Laboratory 
 
 
 (ESSA). 
 
 Newport, Wash 
 
 Coast and Geodetic Survey. 
 
 Nordman, Idaho 
 
 Do. 
 
 Olema, Calif 
 
 Earthquake Mechanisms Laboratory 
 
 (ESSA). 
 Coast and Geodetic Survey. 
 
 Palmer, Alaska (3) 
 
 Rapid City, S. Dak 
 
 South Dakota State School of Mines 
 
 
 and Technology. 
 
 Rincon, Calif 
 
 Earthquake Mechanisms Laboratory 
 
 
 (ESSA). 
 
 Salt Lake City, Utah 
 
 University of Utah. 
 
 See footnotes at end of table. 
 
 45 
 
Table 1. — ^Active teleseismic stations of the United States — Con. 
 
 COAST AND GEODETIC SURVEY AND COOPERATING STATIONS Continued 
 
 San Andreas Lake, Calif 
 
 San Francisco, Calif 
 
 San Juan, Puerto Rico 
 
 Do. 
 
 Coast and Geodetic Survey. 
 Do. 
 
 San Luis, Calif 
 
 Sitka, Alaska 
 
 South Pole, Antarctica 
 
 Stone Canyon, Calif 
 
 Tucson, Ariz 
 
 Ukiah, Calif 
 
 Washington, D.C 
 
 Bureau of Reclamation. 
 Coast and Geodetic Survey. 
 
 Do. 
 Earthquake Mechanisms Laboratory 
 
 (ESSA). 
 Coast and Geodetic Survey. 
 
 Do. 
 
 Do. 
 
 Washington Science Center, 
 Rockville, Md. (3). 
 
 Do. 
 
 JESUIT SEISMOLOGICAL ASSOCIATION STATIONS 
 
 Berlin, N.H 
 
 Berryman, Mo 
 
 Buffalo, N.Y 
 
 Cape Girardeau, Mo 
 
 Chicago, 111 
 
 Cincinnati, Ohio 
 
 Cleveland, Ohio 
 
 Denver, Colo 
 
 Flat River, Mo 
 
 Florissant, Mo 
 
 Greenville, Mo 
 
 Maiden, Mo 
 
 Milford, Ohio 
 
 New Madrid, Mo 
 
 New York, N.Y 
 
 Portageville, Mo 
 
 Rochester, N.Y 
 
 St. Louis, Mo 
 
 Spokane, Wash 
 
 Spring Hill (Mobile Co.), Ala 
 
 Tyson Valley, Mo 
 
 Washington, D.C 
 
 Weston, Mass 
 
 See footnotes at end of table. 
 
 Weston Observatory. 
 St. Louis University. 
 Canisius College. 
 St. Louis University. 
 Loyola University. 
 Xavier University. 
 John Carroll University. 
 Regis College. 
 St. Louis University. 
 
 Do. 
 
 Do. 
 
 Do. 
 Xavier University. 
 St. Louis University. 
 Fordham University. 
 St. Louis University. 
 McQuaid Jesuit High School. 
 St. Louis University. 
 Mount St. Michaels College of Gonzaga 
 
 University. 
 Spring Hill College. 
 St. Louis University. 
 Georgetown University. 
 Weston Observatory. 
 
 46 
 
Table 1. — Active teleseismic stations of the United States — Con. 
 
 PASADENA SEISMOLOGICAL LABORATORY STATIONS 
 (CALIFORNIA INSTITUTE OF TECHNOLOGY) 2 
 
 Barrett, Calif 
 
 China Lake, Calif 
 
 Cottonwood Creek, Calif. 
 
 El Centro, Calif 
 
 Fort Tejon, Calif 
 
 Glamis, Calif 
 
 Goldstone, Calif 
 
 Hayfield, Calif 
 
 Isabella, Calif 
 
 Lake Hughes, Calif 
 
 Mount Wilson, Calif. . . . 
 
 Palomar, Calif 
 
 Pasadena, Calif 
 
 Riverside, Calif 
 
 Santa Barbara, Calif. . . . 
 
 Santa Ynez, Calif 
 
 Tinemaha, Calif 
 
 Woody, Calif 
 
 Barrett Reservoir, City of San Diego. 
 
 Naval Ordnance Test Station, Inyokern. 
 
 Department of Water and Power, City 
 of Los Angeles. 
 
 Imperial Irrigation District. 
 
 Division of Beaches and Parks, State of 
 California. 
 
 California Institute of Technology. 
 
 Jet Propulsion Lab. 
 
 Metropolitan Water District, City of 
 Los Angeles. 
 
 U.S. Army Corps of Engineers, Sacra- 
 mento. 
 
 California Institute of Technology. 
 
 Mount Wilson Observatory. 
 
 Palomar Observatory. 
 
 Kresge and Donnelley Labs. 
 
 City of Riverside. 
 
 Santa Barbara Museum of Natural 
 History. 
 
 California Institute of Technology. 
 
 Bureau of Water Works and Supply, 
 City of Los Angeles. 
 
 Kern County Forestry and Fire Dept. 
 
 UNIVERSITY OF CALIFORNIA STATIONS ^ 
 
 Areata, Calif 
 
 Berkeley (Haviland), Calif. . . 
 Byerly (Berkeley Strawberry), 
 Calif. 
 
 Concord, Calif 
 
 Fresno, Calif 
 
 Granite Creek, Calif 
 
 Hollister, Calif. (5) 
 
 Jamestown, Calif 
 
 Llanada, Calif 
 
 Manzanita Lake, Calif 
 
 Mineral, Calif 
 
 Mount Hamilton, Calif 
 
 Oroville, Calif 
 
 Paraiso, Calif 
 
 Pilarcitos Creek, Calif 
 
 Priest, Calif 
 
 See footnotes at end of table. 
 
 Humboldt State College. 
 University of California . 
 Do. 
 
 Diablo Valley College. 
 Fresno City College. 
 University of California. 
 
 Do. 
 California State Department of Water 
 
 Resources. 
 University of California . 
 Lassen Volcanic National Park. 
 
 Do. 
 Lick Observatory. 
 University of California. 
 
 Do. 
 
 Do. 
 
 Do. 
 
 47 
 
Table 1. — Active teleseismic stations of the United States — Con. 
 
 INDEPENDENT STATIONS 
 
 Anchorage, Alaska 
 
 Ann Arbor, Mich 
 
 Anzar Reservoir, Calif. (9) 
 
 Atlanta, Ga 
 
 Balboa Heights, Canal Zone 2. . . 
 
 Bellingham, Wash 
 
 Bethesda, Md 
 
 Big Mountain, Alaska 
 
 Black Rapids, Alaska 
 
 Blacksburg, Va 
 
 Bloomington, Ind 
 
 Boulder, Colo 
 
 Bowling Green, Ohio 
 
 Canyon Junction, Wyo. (5). . . . 
 
 Chapel Hill, N. C 
 
 Chesbro Reservoir, Calif. (7). . . 
 
 Corvallis, Oreg 
 
 Dallas, Tex 
 
 Dubuque, Iowa 
 
 Dugway, Utah 
 
 East Aurora, N.Y 
 
 El Paso, Tex 
 
 Feather Falls, Calif 
 
 Flagstaff, Ariz 
 
 Fort Sill, Okla 
 
 Glen Cove, N.Y 
 
 Golden, Colo 
 
 Hawaiian Volcanic Observatory, 
 
 Hawaii (16). 
 Honolulu, Hawaii 
 
 Do 
 
 Houston, Tex 
 
 Junction, Tex 
 
 Kentfield, Calif 
 
 Klamath Falls, Oreg 
 
 Laramie, Wyo 
 
 Lawrence, Kans 
 
 Leonard, Okla 
 
 Logan, Utah 
 
 Longmire, Wash 
 
 Los Angeles, Calif 
 
 Los Trancos Woods, Calif. (10). 
 Lubbock, Tex 
 
 See footnotes at end of table. 
 
 Alaska Methodist University. 
 University of Michigan. 
 U.S. Geological Survey. 
 Georgia Institute of Technology. 
 The Panama-Canal Company. 
 Western Washington State College. 
 Bureau of Standards. 
 Geophysical Institute, University of 
 
 Alaska. 
 Do. 
 Virginia Polytechnic Institute. 
 Indiana University. 
 University of Colorado. 
 Bowling Green State University. 
 U.S. Geological Survey. 
 University of North Carolina. 
 U.S. Geological Survey. 
 Oregon State University. 
 Southern Methodist University. 
 Lor as College. 
 University of Utah. 
 East Aurora High School. 
 Texas Western College of the 
 
 University of Texas. 
 California State Department of Water 
 
 Resources. 
 U.S. Geological Survey. 
 Wichita Mountains Observatory, Vela- 
 
 Uniform (Technical direction by 
 
 AFTAC). 
 Private station, Victor Aiello. 
 Colorado School of Mines. 
 U.S. Geological Survey. 
 
 Institute of Geophysics, University of 
 
 Hawaii. 
 University of Hawaii, Manoa Valley. 
 William Marsh Rice University. 
 Texas A. & M. University. 
 College of Marin. 
 Oregon Technical Institute. 
 University of Wyoming. 
 University of Kansas. 
 University of Oklahoma. 
 Utah Agriculture College. 
 University of Washington. 
 Griffith Observatory and Planetarium. 
 U.S. Geological Survey. 
 Texas Technological College. 
 
 48 
 
Table 1. — Active teleseismic stations of the United States — Con. 
 
 INDEPENDENT STATIONS — Continued 
 
 Madison, Wise 
 
 Madison Junction, Wyo. (5). . . 
 Magalia, Calif 
 
 Manhattan, Kans . . 
 
 McKinley, Alaska 
 
 Miles City, Mont 
 
 Morgan town, W. Va 
 
 Mullan, Idaho 
 
 New York, N.Y. 
 
 North Reno, Nev 
 
 Oak Ridge, Tenn 
 
 Ogdensburg, N.J 
 
 Oxford, Miss 
 
 Palisades, N.Y 
 
 Parkfield, Calif. (3) 
 
 Payson, Ariz 
 
 Pedro Dome, Alaska 
 
 Philadelphia, Pa.2 
 
 Portland, Oreg 
 
 Price, Utah 
 
 Reno, Nev 
 
 Rolla, Mo 
 
 San Diego, Calif 
 
 Scottsdale, Ariz 
 
 Seattle, Wash 
 
 Do 
 
 Sheep Creek Mountain, Alaska 
 
 Socorro, N. Mex 
 
 Sparrevohn, Alaska 
 
 State College, Pa 
 
 Sterling Forest, N.Y 
 
 Sunnyside, Utah (6) 
 
 See footnotes at end of table. 
 
 University of Wisconsin. 
 U.S. Geological Survey. 
 California State Department of Water 
 
 Resources. 
 Kansas State University. 
 Geophysical Institute, University of 
 
 Alaska. 
 LASA Data Center, Vela-Uniform 
 
 (Technical direction by AFTAC). 
 West Virginia University. 
 U.S. Department of the Interior, 
 
 Bureau of Mines, Spokane Mining 
 
 Research Laboratory. 
 City College of New York. 
 University of Nevada. 
 Oak Ridge National Laboratory. 
 Lamont Geological Observatory of 
 
 Columbia University. 
 University of Mississippi. 
 Lamont Geological Observatory of 
 
 Columbia University. 
 U.S. Geological Survey. 
 Tonto Forest Observatory, Vela-Uni- 
 form (Technical direction by 
 
 AFTAC). 
 Geophysical Institute, University of 
 
 Alaska. 
 The Franklin Institute. 
 Oregon Museum of Science and 
 
 Industry. 
 Carbon College of the University of 
 
 Utah. 
 University of Nevada. 
 Missouri School of Mines and 
 
 Metallurgy. 
 San Diego State College. 
 Private station, Willard Groene. 
 Private station, Gerald Marshall. 
 University of Washington. 
 Geophysical Institute, University of 
 
 Alaska. 
 New Mexico Institute of Mining and 
 
 Technology. 
 Geophysical Institute, University of 
 
 Alaska. 
 Pennsylvania State University. 
 Lamont Geological Observatory of 
 
 Columbia University. 
 U.S. Geological Survey. 
 
 49 
 
Table 1. — Active teleseismic stations of the United States — Con. 
 
 INDEPENDENT STATIONS — Continued 
 
 Tanana, Alaska 
 
 Geophysical Institute, University of 
 
 Terre Haute, Ind 
 
 Private station, Gerald Shea. 
 
 Tonopah, Nev 
 
 University of Nevada. 
 
 Trinidad, Colo 
 
 Trinidad Junior College. 
 
 Troy, N.Y 
 
 Rensselaer Polytechnic Institute. 
 
 Tumwater, Wash 
 
 University of Washington. 
 
 Unionville, Nev 
 
 University of Nevada. 
 
 Vernal, Utah 
 
 Uinta Basin Observatory, Vela- 
 
 
 Uniform (Technical direction by 
 
 
 AFTAC). 
 
 Wallace, Idaho 
 
 U.S. Department of the Interior, 
 
 
 Bureau of Mines, Spokane Mining 
 
 
 Research Lab. 
 
 Washington, D.C 
 
 Carnegie Institution of Washington, 
 
 
 Dept. of Terrestrial Magnetism. 
 
 Waterville, Maine 
 
 Colby College. 
 
 1 Publishes own station bulletin. 
 
 2 Results published by the Coast and Geodetic Survey. 
 
 3 Correspondence with reference to Pasadena and Berkeley network of stations should be 
 addressed to: Seismological Laboratory, 220 North San Rafael Ave., Pasadena, Calif. 91105, 
 or to Seismographic Stations, University of California, Berkeley, Calif. 94720. 
 
 ( ) The number in parentheses indicates close-in stations at the site. 
 
 50 
 
Table 2. — Lives lost in major United States earthquakes 
 
 LOCALITY 
 
 LIVES 
 LOST 
 
 ►New Madrid, Mo 
 
 San Juan Gapistrano, Calif. 
 
 Hayward, Calif 
 
 Owens Valley, Calif 
 
 Charleston, S.C 
 
 San Jacinto, Calif 
 
 San Francisco, Calif 
 
 Imperial Valley, Calif 
 
 Puerto Rico (killed by tsunami from earthquake in Mona 
 
 Passage) 
 
 Santa Barbara, Calif 
 
 Do 
 
 Humboldt Co., Calif 
 
 Long Beach, Calif 
 
 Kosmo, Utah 
 
 Helena, Mont 
 
 Imperial Valley, Calif 
 
 Hawaii (killed by tsunami from earthquake in Aleutians) . . 
 
 Puget Sound, Wash 
 
 Kern Co., Calif 
 
 Eureka-Arcata, Calif 
 
 Oakland, Calif 
 
 Khantaak Island and Lituya Bay, Alaska 
 
 Hebgen Lake, Mont 
 
 Hilo, Hawaii (killed by tsunami from earthquake off the 
 
 coast of Chile) 
 
 Prince William Sound, Alaska (tsunami claimed nearly 
 
 all those killed along Gulf of Alaska and west coast of 
 
 the United States) 
 
 Puget Sound, Wash 
 
 Several 
 40 
 
 51 
 
Table 3. — Damage (in dollars) caused by strong United States 
 
 earthquakes 
 
 LOCALITY 
 
 1865 
 1868 
 1872 
 1886 
 1892 
 1898 
 1906 
 
 1915 
 1918 
 
 1918 
 1925 
 1933 
 1935 
 1940 
 1941 
 1941 
 1944 
 1946 
 
 1949 
 1949 
 1951 
 1952 
 1954 
 1954 
 1955 
 1955 
 1957 
 
 1957 
 1959 
 1960 
 
 1961 
 1964 
 
 1965 
 1966 
 
 San Francisco, Calif 
 
 do 
 
 Owens Valley, Calif 
 
 Charleston, S.C 
 
 Vacaville, Calif 
 
 Mare Island, Calif 
 
 San Francisco, Calif 
 
 Fire loss 
 
 Imperial Valley, Calif 
 
 Puerto Rico (tsunami damage from earthquake in 
 Mona Passage) 
 
 San Jacinto and Hemet, Calif 
 
 Santa Barbara, Calif 
 
 Long Beach, Calif 
 
 Helena, Mont 
 
 Imperial Valley, Calif 
 
 Santa Barbara, Calif 
 
 Torrance-Gardena, Calif 
 
 Cornwall, Canada-Massena, N.Y 
 
 Hawaii (tsunami damage from earthquake in Aleu- 
 tians) 
 
 Puget Sound, Wash 
 
 Terminal Island, Calif, (oil wells only) 
 
 do 
 
 Kern County, Calif 
 
 Eureka-Arcata, Calif 
 
 Wilkes-Barre, Pa .• 
 
 Terminal Island, Calif, (oil wells only) 
 
 Oakland-Walnut Creek, Calif 
 
 Hawaii (tsunami damage from earthquake in Aleu- 
 tians) 
 
 San Francisco, Calif 
 
 Hebgen Lake, Mont, (damage to timber and roads). . 
 
 Hawaii and west coast of United States (tsunami 
 damage from earthquake off the coast of Chile) . . . 
 
 Terminal Island, Calif, (oil wells only) 
 
 Alaska and west coast of United States (tsunami 
 damage from earthquake near Anchorage, Alaska; 
 includes earthquake damage in Alaska) 
 
 Puget Sound, Wash 
 
 Dulce, N.Mex 
 
 Dollars 
 500, 000 
 350, 000 
 250, 000 
 
 23, 000, 000 
 225, 000 
 
 1, 460, 000 
 
 24, 000, 000 
 500, 000, 000 
 
 900, 000 
 
 4, 000, 000 
 200, 000 
 
 8, 000, 000 
 40, 000, 000 
 
 4, 000, 000 
 
 6, 000, 000 
 
 100, 000 
 
 1,000,000 
 
 2, 000, 000 
 
 25, 000, 000 
 25, 000, 000 
 
 9, 000, 000 
 
 3, 000, 000 
 60, 000, 000 
 
 2, 100, 000 
 1, 000, 000 
 
 3, 000, 000 
 1, 000, 000 
 
 3, 000, 000 
 1, 000, 000 
 
 11,000,000 
 
 25, 500, 000 
 
 4, 500, 000 
 
 500, 000, 000 
 
 12,500,000 
 
 200, 000 
 
 52 
 
SEISMOLOGICAL PUBLICATIONS 
 
 of the 
 NATIONAL EARTHQUAKE 
 INFORMATION CENTER 
 
 The following list of publications relates to the earthquake 
 investigation activities of the National Earthquake Information 
 Center and may be obtained at the stipulated prices from the 
 sources indicated. Remittance may be made by postal money order, 
 express money order, or check. Postage stamps cannot be accepted. 
 Foreign remittance must be by international money order. 
 
 Although the publications are partially technical in character, 
 many of them are readily understandable by the layman, or 
 educator interested in the more general aspects of earthquake in- 
 formation and present-day research. There is much information 
 of interest to actuaries, and to architects and engineers interested 
 in the design of earthquake-resistive structures. The reports cover 
 all seismic activity observed or recorded in the United States and 
 outlying possessions, or give references to publications issued by 
 other organizations in which such information may be found. 
 
 Because this list is constantly changing, a separate report entitled 
 List of Seismological Publications may be obtained each year by 
 writing to this Center. The present publication. Earthquake In- 
 vestigation in the United States^ is revised about every 5 years. 
 
 53 
 
List of Seismological Publications 
 
 TITLE OF REPORT 
 
 Price 
 
 United States Earthquakes, 1928-1935 (Reprint) 
 
 United States Earthquakes, 1936-1945 (Reprint) 
 
 United States Earthquakes, 1946 
 
 United States Earthquakes, 1947 
 
 United States Earthquakes, 1948 
 
 United States Earthquakes, 1949 
 
 United States Earthquakes, 1950 
 
 United States Earthquakes, 1951 
 
 United States Earthquakes, 1 952 
 
 United States Earthquakes, 1953 
 
 United States Earthquakes, 1954 
 
 United States Earthquakes, 1955 
 
 United States Earthquakes, 1956 
 
 United States Earthquakes, 1957 
 
 United States Earthquakes, 1958 
 
 United States Earthquakes, 1959 
 
 United States Earthquakes, 1960 
 
 United States Earthquakes, 1961 
 
 United States Earthquakes, 1962 
 
 United States Earthquakes, 1963 
 
 United States Earthquakes, 1964 _ 
 
 United States Earthquakes, 1965 
 
 United States Earthquakes, 1966 
 
 United States Earthquakes, 1967 
 
 Earthquake History of the United States, Part I — Stronger Earth* 
 
 quakes of the United States (exclusive of California and Western 
 
 Nevada). Pub. 41-1 (Revised 1963 Edition) 
 
 Earthquake History of the United States, Part II — Stronger 
 
 Earthquakes of California and Western Nevada. Pub. 41-1 
 
 (Revised 1963 Edition). 
 
 Earthquake Investigations in the Western United States, 1931- 
 
 1964, Pub. 41-2 
 
 Principles Underlying the Interpretation of Seismograms, Special 
 
 Publication 254 (Revised 1966 Edition) 
 
 Tsunami — The Story of the Seismic Sea Wave Warning System 
 The Puget Sound, Washington, Earthquake of April 29, 1965. . 
 
 The Parkfield, California, Earthquake of June 27, 1966 
 
 The Fairbanks, Alaska, Earthquakes of June 21, 1967 
 
 The Prince William Sound, Alaska, Earthquake of 1964 and 
 
 Aftershocks, Volume I 
 
 The Prince William Sound, Alaska, Earthquake of 1964 and 
 
 Aftershocks, Volume II, Part A 
 
 A Preliminary Study of Engineering Seismology Benefits 
 
 The Tsunami of March 28, 1 964, as Recorded at Tide Stations . 
 
 $1.75** 
 1.25 
 .30* 
 .35* 
 .30* 
 .35* 
 .25* 
 .25* 
 .60* 
 .35* 
 .55* 
 .30* 
 .45* 
 .60* 
 .40* 
 .70* 
 .50* 
 .55* 
 .60** 
 .40** 
 .55** 
 .55** 
 .70** 
 2.25 
 
 .70* 
 
 .30** 
 
 2. 75** 
 
 2.00** 
 .35** 
 .40** 
 .45** 
 .45** 
 
 6. 50** 
 
 5. 50** 
 .35** 
 .50** 
 
 *Available from the National Earthquake Information Center, ESS A, 
 Coast and Geodetic Survey, Rockville, Md. 20852. 
 
 **Available from the Superintendent of Documents, U.S. Government 
 Printing Office, Washington, D.C. 20402. 
 
 54 
 
The publications listed in the United States Earthquakes series, 
 the annual seismological report of the National Earthquake Infor- 
 mation Center, are primarily statistical. They are catalogs, 
 beginning in 1928, of earthquakes in the United States and 
 outlying territories, in this respect adding materially to the re- 
 stricted territory covered by Publication 41-1, Parts I and II. 
 Beginning with the 1933 report, a section on the results of the 
 strong-motion work of the Coast and Geodetic Survey was 
 added. This section is designed primarily to furnish structural 
 engineers, and other interested groups, with precise data on 
 destructive ground motions. Also included are sections discussing 
 geodetic work of seismological interest; tidal disturbances of 
 seismic origin ; and fluctuations in well-water levels that correspond 
 to earthquake occurrences. 
 
 Publication 41-1 {Revised 1963 Edition) , Earthquake History of 
 the United States, Part I, is a catalog of the most important shocks 
 of historical record through 1963. It contains descriptive text on 
 all shocks listed, in addition to regional tables which list earth- 
 quakes chronologically with their locations, aff'ected areas, and 
 intensities. Epicenter maps are included that show earthquake 
 distribution in the United States, including Alaska and Hawaii. 
 
 Publication 41-1 {Revised 1963 Edition), Earthquake History 
 of the United States, Part II, is a 48-page summary of the stronger 
 earthquakes of California and western Nevada through 1963. 
 Parts I and II are similar in extent of detail. 
 
 Publication 41-2, Earthquake Investigations in the Western 
 United States, 1931-1964, is a 256-page report describing the 
 seismological work carried out under the auspices of the Federal 
 Government during this period. It is primarily of engineering in- 
 terest as it concerns the precise measurement of ground and build- 
 ing motion resulting from natural and artificial causes. The 
 publication describes in considerable detail the development of 
 instruments, the organization of field parties, the analysis of 
 records, and the collection of noninstrumental seismic data. A 
 large quantity of observational data is given, including information 
 on normal and forced vibrations of buildings, elevated water tanks, 
 bridges, and other structures. Structural damage resulting from 
 earthquakes of the western U.S. since 1933 is described in the last 
 section. 
 
 Special Publication 254, Principles Underlying the Interpreta- 
 tion of Seismograms, is a 50-page publication designed to meet the 
 needs of the student. Included are sections on seismic waves 
 
 55 
 
and earth structure, the response of seismographs to seismic waves, 
 travel-time tables and charts, interpretation of seismograms, and 
 other items such as intensity and magnitude. There are 13 illus- 
 trations and four large travel-time charts. 
 
 Tsunami — The Story of the Seismic Sea Wave Warning Sys- 
 tem, is a brochure describing the operation of the System in the 
 Pacific. It includes the methods employed to warn residents of 
 a possible seismic sea wave (tsunami) and outlines cautionary 
 steps to be taken when an alarm is given. 
 
 The Puget Sound, Washington, Earthquake of April 29, 1965, 
 gives a detailed description of the seismological and engineering 
 aspects of this earthquake. Included are the geology and seismic 
 history of the Puget Sound region and a discussion of the intensity, 
 direction of faulting, and foreshocks and aftershocks. The report 
 is highlighted by a descriptive analysis of the damage incurred 
 (including 16 photos of damage), and a discussion of strong- 
 motion measurements. Eighteen additional illustrations concerning 
 various aspects of the earthquake are included. 
 
 The Parkfield, California, Earthquake of June 27, 1966, contains 
 information very similar to the report described above. However, 
 included in this report are 26 damage photos and an additional 
 35 illustrations concerning various aspects of the shock. 
 
 The Fairbanks, Alaska, Earthquakes of June 21, 1967, similar 
 in content to the two previously described, details the effects of the 
 earthquake series in Fairbanks in June 1967. It contains 10 photos 
 of earthquake effects and 31 line-cut illustrations of other aspects 
 of the principal shock and aftershocks. 
 
 The Prince William Sound, Alaska, Earthquake of 1964 and 
 Aftershocks, Volume I, describes the equipment, instrumentation, 
 survey systems, and specific procedures used in the Coast and 
 Geodetic Survey's investigations of this earthquake. It sum- 
 marizes the procedures used in coordinated seismological, geodetic, 
 photogrammetric, oceanographic, hydrographic, and cartographic 
 studies directed toward determining both the causal factors and 
 associated effects of this earthquake series. Also included is a large 
 section discussing the geology and seismic history of Alaska, includ- 
 ing tables covering felt Alaskan earthquakes since 1786. This 
 263-page book contains 179 illustrations. 
 
 The Prince William Sound, Alaska, Earthquake of 1964 and 
 Aftershocks, Volume II, Part A, is directed toward engineers, 
 architects, builders, and all others seriously interested in the rea- 
 sons for the extensive damage to buildings and other properties 
 
 56 
 
in Anchorage from the 1964 earthquake. The mode of failure 
 for most major buildings in Anchorage is described, and the dam- 
 age analysis clearly indicates danger points in some modern design 
 methods and construction practices. The resulting damage pat- 
 terns to modern construction are clear indications of what can be 
 expected should another such shock strike elsewhere in the popu- 
 lated United States. The report contains 392 pages, 599 illustra- 
 tions, 59 tables, and a phonograph record in the end pocket that 
 relates a personal, on-the-spot description of the earthquake as 
 it was occurring. 
 
 A Preliminary Study of Engineering Seismology Benefits is a 
 report that analyzes the usefulness of seismological information 
 available to the construction industry, as well as the economic 
 consequences of ignoring such information. The report examines 
 in some measure how engineering seismology and the use of Coast 
 and Geodetic Survey data have affected building codes, and in- 
 vestigates the benefits derived from the incorporation of earth- 
 quake-resistive features into the construction of public buildings, 
 particularly schools. Included are eight photos of earthquake 
 damage to California schools, several diagrams and charts, and two 
 tables. 
 
 The Tsunami of March 28, 1964, as Recorded at Tide Stations, 
 C&GS 33, is an 86-page report describing the tsunami generated 
 by the great Prince William Sound earthquake. The report con- 
 tains 105 reproductions of tide curves showing the tsunami, and 
 eight curves showing oscillations induced by the long-period seismic 
 waves — six in the Gulf of Mexico and two at Arkansas damsites. 
 A brief history of the Tsunami Warning System and a report of its 
 operation during the tsunami warning action are included. 
 
 Note — The Coast and Geodetic Survey maintains mailing lists 
 for issuing notices of reports. If you desire to receive notices of 
 seismological publications as they are issued, address your request 
 to the National Earthquake Information Center (see address in 
 footnote on page 54) . 
 
 The following processed reports issued by the National Earth- 
 quake Information Center are not available to the general public. 
 They are primarily intended for cooperating seismological groups, 
 research institutions, universities, and libraries. Those within these 
 categories who desire to receive these reports as issued may re- 
 quest addition of their names to the mailing lists indicated below. 
 
 57 
 
1. Preliminary Determination of Epicenters. These reports list 
 the approximate epicentral locations of earthquakes occurring 
 in any area of the world. They give origin time of the earthquakes, 
 latitude and longitude, region of occurrence and comments, depth, 
 magnitude, and other miscellaneous information. They are issued 
 biweekly on the "PDE Mailing List." 
 
 2. Earthquake Data Report. This report contains data used in 
 the computation of the PDE cards above. It is issued twice weekly 
 on the "EDR Mailing List," to those having need for station 
 arrival times, individual distances, azimuths, and travel-time 
 residuals. 
 
 3. Seismological Bulletin. This publication is a register of seis- 
 mogram interpretations for 24 regular and cooperating seismo- 
 graph stations. Refined epicenters are listed in this monthly bul- 
 letin. It is available on the "CGS-7 Mailing List." 
 
 4. Abstracts of Earthquake Reports for the United States. This 
 quarterly report originally summarized the earthquake formation 
 furnished by various institutions and observers on the Pacific 
 Coast and in the Western Mountain region of the United States. 
 In January 1967, the report was expanded to include coverage 
 of the complete United States, Canal Zone, Virgin Islands, and 
 Puerto Rico. The information is quite detailed, listing each earth- 
 quake reported felt and its effects. The report is available on the 
 "CGS-3 Mailing List." 
 
 5. Quarterly Engineering Seismology Bulletin. This report per- 
 tains to the strong-motion earthquake work of the Coast and Geo- 
 detic Survey on the Pacific Coast of the United States and in other 
 regions. It contains analyses of all accelerograph records obtained 
 during the quarter, and may be obtained through the "CGS-5 
 Mailing List." 
 
 58 
 
 U.S. GOVERNMENT PRINTING OFFICE: 1969 O— 335-146 
 
PENN STATE UNIVERSITY LIBRARIES 
 
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