Earthquakes in the United States, July-September 1982

Dallas L. Peck, Director

Introduction................................................................. Cl Discussion of tables ......................................................... 1 Modified Mercalli Intensity Scale of 1931.................................... 8 Acknowledgments.............................................................. 30 References cited............................................................. 30

FIGURE 1. "Earthquake Report" form.......................................... C2

ILLUSTRATIONS

2. Map showing standard time zones of the conterminous United States. 4
3. Map showing standard time zones of Alaska and Hawaii.............. 5
4. Map of earthquake epicenters in the conterminous United States for July-September 1982............................................... 6
5. Map of earthquake epicenters in Alaska for July-September 1982.... 7
6. Map of earthquake epicenters in Hawaii for July-September 1982.... 8
7. Isoseismal map for the central California earthquake of 18 August 1982.............................................................. 20
8. Isoseismal map for the California-Nevada border region earthquake of 24 September 1982.............................................. 27

TABLES

Page TABLE 1. Summary of U.S. earthquakes for July-September 1982: Alaska........................................................ CIO Arkansas...................................................... 12 California.................. .................................. 12 California Off the coast..................................... 14 Colorado...................................................... 14 Hawaii........................................................ 14 Idaho......................................................... 14 Illinois...................................................... 14 Maine......................................................... 15 Missouri...................................................... 15 Montana....................................................... 15 Nevada........................................................ 15 New Mexico.................................................... 15 New York...................................................... 15 Oregon Off the coast......................................... 15 South Carolina................................................ 15 South Dakota.................................................. 16 Tennessee..................................................... 16 Washington.................................................... 16 Washington Off the coast..................................... 16 Wyoming....................................................... 16

2. Summary of macroseismic data for U.S. earthquakes, July-September 1982:

Alaska........................................................ C16 Arkansas...................................................... 18 California.................................................... 18 Colorado...................................................... 24 Georgia....................................................... 24 Hawaii........................................................ 24 Idaho......................................................... 25 Illinois...................................................... 25 Iowa.......................................................... 25 Minnesota..................................................... 25 Missouri...................................................... 25 Montana....................................................... 26 Nevada........................................................ 26 New Mexico.................................................... 27 New York...................................................... 28 North Carolina................................................ 28 South Carolina................................................ 28 South Dakota.................................................. 28 Tennessee..................................................... 28 Washington.................................................... 29 Wyoming....................................................... 29

IV The earthquake information in this publication supplements that published by the U.S. Geological Survey (USGS) in the National Earthquake Information Service (NEIS) publications, PDE ("Preliminary Determination of Epicenters") and "Preliminary Determination of Epicenters Monthly Listing," by providing detailed felt and intensity data for U.S. earthquakes. The purpose of this circular is to provide a complete listing of macroseismic effects of earthquakes, which can be used in risk studies, nuclear powerplant site evaluations, seismicity studies, and to answer inquiries by the public.

This publication contains two major sections. The first part (table 1), which is mainly concerned with data obtained by seismographs, is a tabular listing of earthquakes in chronological order by State, consisting of the following basic information: date, origin time, hypocenter, magnitude, maximum intensity, and computational source of the hypocenter. The second section, which concerns intensity information, consists of isoseismal or intensity maps and table 2. This section may contain information on events that were felt but were not listed in the PDE because there was not enough instrumental data to obtain a solution. The list of earthquakes in table 1 was compiled from those located in the United States or nearby offshore areas that were published in the PDE; from aftershock studies carried out by the U.S. Geological Survey and other organizations; from hypocenters in California above magnitude 3.0 supplied by the California Institute of Technology, Pasadena, the University of California, Berkeley, and other offices of the U.S. Geological Survey; from hypocenters in Hawaii supplied by the Hawaiian Volcano Observatory; and from other institutions as listed in the acknowledgments. Known or suspected explosions are also listed in table 1 and table 2.

The intensities and macroseismic data were compiled from information obtained from postal

Cl

questionnaires, from newspaper articles, and from other Government agencies, State institutions, local organizations, and individuals. (See "Acknowledgments" for a list of collaborators.) Figure 1 is the questionnaire in use by the USGS. Other types of questionnaires are used by State agencies, engineering firms, and other Government agencies to collect intensity data. Anyone wishing to submit felt or damage information on earthquakes for inclusion in future reports should send it to the U.S. Geological Survey, United States Earthquakes Project, Stop 967, Box 25046, Denver Federal Center, Denver, CO 80225. Copies of the current "Earthquake Report" questionnaire can be obtained at this address.

the primary source of macroseismic data to carry out an intensity survey; however, on-site field investigations are made following earthquakes that do significant damage. The "Earthquake Report" forms are mailed to postmasters within the area affected by the earthquake. The completed forms are returned to the USGS, where they are evaluated and intensity values are assigned to individual locations. For large or significant earthquakes, the intensity observations are plotted and isoseismal maps are prepared. Note that the isoseismals represent a general intensity level and that they do not necessarily agree with every individual observation.

1 and table 2 include the date, origin time, hypocenter (epicenter and focal depth), magnitude, intensity, and source of the computed solution. The origin time and date are listed in Universal Coordinated Time (UTC) and local standard time based on the time-zone maps in figures 2 and 3. The epicenters, which were The USGS uses the postal questionnaire as

DISCUSSION OF TABLES

The parameters for the earthquakes in table FIGURE 1. Example of the "Earthquake Report" form used for evaluating the intensities of earthquakes. A, front side.

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FIGURE 1. Example of the "Earthquake Report" form used for evaluating the intensities of earthquakes. B, reverse side.

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FIGURE 2. Standard time zones of the conterminous United States. The number in each zone shows the number of hours to be subtracted from Universal Coordinated Time to convert to local standard time. (Subtract 1 hour less for local daylight-saving time.)

taken from those published in the PDE, or from other sources as noted, are listed here to two decimals. The accuracy of the epicenters is not necessarily indicated by the number of decimals listed. The epicenters located by the NEIS usually are accurate to two-tenths of a degree or less. In general, epicenters located offshore are less accurate than those on land, even though they are listed to two decimals. In regions covered by dense networks of seismographs such as California, epicenter accuracy is significantly better than the two-tenths of a degree listed. Depths are listed to the nearest whole kilometer.

Figures 4-6 are maps summarizing the earthquake activity for the conterminous United States, Alaska, and Hawaii for the period July-September 1982. The magnitudes represented in these figures are based on ML, Mn, or MD; if none of these were computed, then on MS; and finally on mb, when it was the only magnitude computed.

The magnitude values listed in tables 1 and 2 were furnished by cooperating institutions or determined by USGS. The computational sources

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are labeled according to the assigned letter codes shown in headnotes to tables 1 and 2; the letter follows the value listed under the column heading "Magnitude." In table 1, the absence of a letter code indicates that the source is USGS. The magnitude values calculated by USGS are based on the following formulas:

MS= .661ogEH-3 .3 , (1)

as adopted by the International Association of Seismology and Physics of the Earth's Interior (IASPEI; Bath, 1966, p. 153), where A is the maximum vertical surface-wave ground amplitude, in micrometers; T is the period, in seconds, and 18<T<22; and D is the distance, in geocentric degrees (station to epicenter), and 20°<DO60°. No depth correction is made for depths less than 50 km.

mb=log(A/T)+Q(D,h), (2)

as defined by Gutenberg and Richter (1956), except that T, the period in seconds, is restricted to O.KTO.O, and A, the ground amplitude in micrometers, is not necessarily the max-FIGURE 3. Standard time zones of Alaska and Hawaii. The number in each zone shows the number of hours to be subtracted from Universal Coordinated Time to convert to local standard time. (Subtract 1 hour less for local daylight-saving time.)

imum of the P-wave group. Q is a function of distance D and depth h, where D>5 0 .

as defined by Richter (1958, p. 340), where A,,is the maximum trace amplitude in millimeters, written by a Wood-Anderson torsion seismometer, and log A is a standard value as a function of distance, where the distance is <600 km. ML values are also calculated from other seismometers by conversion of recorded ground motion to the expected response of the torsion seismometer.

Mn=3.75+0.90(logD)+log(A/T) (4)

Mn=3.30+1.66(logD)+log(A/T)

as proposed by Nuttli (1973), where A/T is expressed in micrometers per second, calculated 165° 150C

ML=logA-logA<> , (3)

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from the vertical-component 1-second Lg waves, and D is the distance in geocentric degrees.

MD is used in this publication for the duration or coda length magnitude. MD is usually computed from the difference, in seconds, between Pn-or Pg-wave arrival time and the time the final coda amplitude decreases to the background-noise amplitude. These magnitudes are normally correlated with ML or mbLg so that resulting magnitudes are compatible. Thus the formulas vary for different geographic regions and seismograph systems.

All of the intensity values (indicated by Roman numerals) listed in this summary were determined, using the Modified Mercalli Intensity Scale of 1931 (Wood and Neumann, 1931) shown below, from the evaluation of "Earthquake Report" forms; from field reports by U.S. Geological Survey personnel, engineering firms, or universities; and from detailed macroseismic data communicated to the USGS by people in the

o Magnitude <5.0 O Magnitude 5.0-5.9 Magnitude <5 Magnitude Magnitude

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VII. Frightened all general alarm, all ran

VIII. Fright general alarm approaches panic.

IX. Panic general. Cracked ground conspicuoutdoors. Some, or many, found it difficult to stand. Noticed by persons driving motor cars. Trees and bushes shaken moderately to strongly. Waves on ponds, lakes, and running water. Water turbid from mud stirred up. Incaving to some extent of sand or gravel stream banks. Rang large church bells, etc. Suspended objects made to quiver. Damage negligible in buildings of good design and construction, slight to moderate in well-built ordinary buildings, considerable in poorly built or badly designed buildings, adobe houses, old walls (especially where laid up without mortar), spires, etc. Cracked chimneys to considerable extent, walls to some extent. Fall of plaster in considerable to large amount, also some stucco. Broke numerous windows, furniture to some extent, shook down loosened brickwork and tiles. Broke weak chimneys at the roof-line (sometimes damaging roofs). Fall of cornices from towers and high buildings. Dislodged bricks and stones. Overturned heavy furniture, with XI. Disturbances in ground many and widedamage from breaking. Damage considerable to concrete irrigation ditches.

Disturbed persons driving motor cars. Trees shaken strongly branches, trunks, broken off, especially palm trees. Ejected sand and mud in small amounts. Changes: temporary, permanent; in flow of springs and wells; dry wells renewed flow; in temperature of spring and well waters. Damage slight in structures (brick) built especially to withstand earthquakes. Considerable in ordinary substantial buildings, partial collapse: racked, tumbled down, wooden houses in some cases; threw out panel walls in frame structures, broke off decayed piling. Fall of walls. Cracked, broke, solid stone walls seriously. Wet ground to some extent, including ground on steep XII. Damage total practically all works of slopes. Twisting, fall, of chimneys, columns, monuments, also factory stacks, towers. Moved conspicuously, overturned, very heavy furniture.

ously. Damage considerable in (masonry) structures built especially to withstand earthquakes: Threw out of plumb some wood-frame houses built especially to withstand earthquakes; great in substantial (masonry) buildings, some collapse in large part; or wholly shifted frame buildings off foundations, racked frames; serious to reservoirs; underground pipes sometimes broken. Cracked ground, especially when loose and wet, up to widths of several inches; fissures up to a yard in width ran parallel to canal and stream banks. Landslides considerable from river banks and steep coasts. Shifted sand and mud horizontally on beaches and flat land. Changed level of water in wells. Threw water on banks of canals, lakes, rivers, etc. Damage serious to dams, dikes, embankments. Severe to well-built wooden structures and bridges, some destroyed. Developed dangerous cracks in excellent brick walls. Destroyed most masonry and frame structures, also their foundations. Bent railroad rails slightly. Tore apart, or crushed endwise, pipe lines buried in earth. Open cracks and broad wavy folds in cement pavements and asphalt road surfaces.

spread, varying with ground material. Broad fissures, earth slumps, and land slips in soft, wet ground. Ejected water in large amounts charged with sand and mud. Caused sea-waves ("tidal" waves) of significant magnitude. Damage severe to wood-frame structures, especially near shock centers. Great to dams, dikes, embankments often for long distances. Few, if any (masonry) structures remained standing. Destroyed large well-built bridges by the wrecking of supporting piers, or pillars. Affected yielding wooden bridges less. Bent railroad rails greatly, and thrust them endwise. Put pipe lines buried in earth completely out of service.

construction damaged greatly or destroyed. Disturbances in ground great and varied, numerous shearing cracks. Landslides, falls of rock of significant character, slumping of river banks, etc., numerous and extensive. Wrenched loose, tore off, large rock masses. Fault slips in firm rock, with notable horizontal and vertical offset displacements. Water channels, surface and underground, disturbed and modified greatly. Dammed lakes, produced waterfalls, deflected rivers, etc. Waves seen on ground surfaces (actually seen, probably, in some cases). Distorted lines of sight and level. Threw objects upward into the air.

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23 37 34.1 23 49 08.5 03 48 17.2 14 34 02.1 21 26 27.6 05 39 01.8 05 06 51.4 12 34 51.8 05 02 06.3 05 29 39.6 09 44 43.4 19 24 47.4 05 56 20.6 01 41 50.4 06 29 15.5 20 23 31.4 02 34 17.3 06 09 53.7 18 02 32.0 14 45 03.1 00 41 55.3 04 53 58.6 08 37 25.8 19 53 46.1 14 11 00.6 152.83 W. 179.94 W. 145.68 W. 152.31 W.

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23 27 i12 07 19 12 59 13 30 22 17 11 37 11 51 20 09 21 03 00 02 01 03 02 55 11 21 11 37 10 43 12 44 17 01 18 57 08 51 08 59 11 48 01 55 21 32 16 09 05 03 16 18 16 49 19 17 01 35 00 23 03 02 04 38 16 20 16 43

46.2 43.2 19.8 124.44 W. 125.50 W. 124.50 W. 124.81 W. 124.85 W. 124.82 W. 125.24 W. 119.02 W. 119.98 W.

155.61 W. 155.38 W. 155.37 W. 155.52 W. 155.24 W. 157.18 W. 155.63 W. 155.76 W. 155.10 W. 155.19 W. 155.10 W. 155.07 W. 155.22 W. 155.22 W. 155.27 W. 155.27 W. 155.13 W. 155.27 W. 156.03 W. 156.01 W. 155.64 W. 155.40 W. 155.22 w. 155.26 W. 155.42 W.

155.19 W. 155.60 W. 155.12 W. 155.40 W. 155.28 W. 155.26 W. 155.18 W. 155.60 W.

114.40 W. 115.06 W. 111.46 W. 16 38

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JULY 2 JULY 13 JULY 26 JULY 26 JULY 27 JULY 27 JULY 27 JULY 27 JULY 27 JULY 27 JULY 27 JULY 27 AUG. 13 AUG. 13 REPT. 18 03 30 24.1 08 24 22.6 13 05 49.0 14 55 18.7 04 49 59.7 04 51 44.1 06 02 03.9 06 16 55.2 06 22 58.4 06 46 13.7 07 22 12.6 09 02 36.0 02 23 57.1 11 27 05.4 07 31 33.5 42.71 N. 43.26 N. 43.91 N. 44.03 N. 43.94 N. 43.94 N. 43.95 N. 43.96 N. 43.88 N. 44.32 N. 43.96 N. 43.89 N. 43.91 N. 44.02 N. 43.57 N.

OREGON OFF THE COAST 126.62 W. 126.41 W. 128.38 W. 128.48 W. 128.33 W. 128.38 W. 128.36 W. 128.18 W. 128.44 W. 128.87 W. 128.22 W. 128.36 W. 128.30 W. 128.77 W. 127.18 W. ROUTH CAROLINA

CIS

4.2 4.0 G JULY 13 00 A.M. PST 4.8 4.5 G JULY 26 05 A.M. PRT 4.8 3.7 G JULY 26 06 A.M. PRT 4.3 5.1 G JULY 26 08 P.M. PRT 4.8 5.0 4.5 G JULY 26 10 P.M. PST 4.9 5.1 G JULY 26 10 P.M. PRT 5.1 4.8 G JULY 26 10 P.M. PRT 5.2 3.8 G JULY 26 10 P.M. PRT 4.1 4.4 4.2 G JULY 27 01 A.M. PRT 4.5 3.7 3.9 4.0 G JULY 1 07 P.M. PRT

G JULY 26 08 P.M. PST

G JULY 26 11 P.M. PRT G AUG. 12 06 P.M. PRT G AUG. 13 03 A.M. PRT G REPT. 17 11 P.M. PRT 16 01 35.6 10 11 09.4 21 57 42.4 22 19 16.9 02 05 56.3 02 06 28.0

03 02 07.5 17 32 33.2 10 09 23.9 36.26 N. 35.20 N. 35.68 N. 35.69 N. 36.24 N. 36.26 N.

47.25 N. 47.69 N. 46.87 N.

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89.45 W.

84.51 W.

84.24 W.

84.25 W.

89.42 W.

89.43 W.

119.95 W. 122.03 W. 121.07 W. 30 September (G) Central Alaska

27 August (G) Andreanof Islands, Aleutian Islands Origin time: 11 59 00.6 Epicenter: 51.39 N., 178.28 W. Depth: 49 km Magnitude: 5.1mb(G), 4.4MS(G), 4.9ML(M)

Felt on Adak Island (M).

30 August (G) Alaska Peninsula Origin time: 13 30 06.1 Epicenter: 54.53 N., 161.62 W. Depth: 35 km Magnitude: 5.2mb(G), 4.3MS(G), 5.5ML(M)

Felt at Sand Point (press report).

1 September (G) Southern Alaska Origin time: 06 19 24.8 Epicenter: 61.22 N., 150.82 W. Depth: 93 km Magnitude: 3.8ML(G) Intensity III: Anchorage (M).

6 September (G) Kodiak Island region Origin time: 07 48 54.9 Epicenter: 56.84 N., 151.59 W. Depth: Normal Magnitude: 5.7mb(G), 5.9mb(B), 6.0mb(P) 5.6MS(G), 5.4MS(B), 6.0ML(M) Intensity III: Kodiak (press report).

CIS July (K) Central Arkansas

July (K) New Madrid region

August (K) Central Arkansas

September (K) Central Arkansas

September (K) Central Arkansas

July (P) Southern California Origin time: 09 48 05.1 Epicenter: Depth: Magnitude:

Felt at Fairbanks (M).

Origin time: 04 13 49.8 Epicenter: 35.18 N., 92.23 W. Depth: 6 km Magnitude: 3.8Mn(T), 3.8MD(K)

Felt in the epicentral area (K).

Origin time: 04 30 52.7

See Missouri listing.

Origin time: 11 12 31.7 Epicenter: 35.18 N., 92.23 W. Depth: 4 km Magnitude: 3.2Mn(T), 2.9MD(K)

Felt at Enola and Naylor (K).

Origin time: 23 17 05.5 Epicenter: 35.20 N., 92.23 W. Depth: 5 km Magnitude: 3.5Mn(T), 3.2MD(K)

Felt in the Enola-Naylor area (K).

Origin time: 10 22 32.5 Epicenter: 35.19 N., 92.22 W. Depth: 3 km Magnitude: 3.1Mn(G), 3.8Mn(T), 2.7MD(K)

Felt in the Enola-Naylor area (K).

Intensity III; Naylor (press report).

Origin time: 12 44 03.4 Epicenter: 35.77 N., 117.73 W. 65.75 N., 145.06 W. 15 km 4.3ML(M)

ARKANSAS CALIFORNIA Continued CALIFORNIA Continued

Depth: 8 km Magnitude: 3.6ML(P), 3.7ML(B) Intensity IV; China Lake, Ridgecrest.

7 July (P) Southern California Origin time: 08 44 33.7 Epicenter: 34.15 N., 116.70 W. Depth: 11 km Magnitude: 3.6ML(P)

Felt at Palm Desert and Lucerne Valley (P)

and at Palm Springs (press report).

18 July (P) Central California Origin time: Epicenter: Depth: Magnitude:

Felt at Hollister (B).

18 July (P) Southern California Origin time: Epicenter: Depth: Magnitude: Anaheim (press report), Santa Intensity IV:

Ana.

18 July (B) Northern California Origin time: Epicenter Depth: Magnitude:

Felt at Paskenta (B).

29 July (P) Southern California Origin time: 05 50 08.6 Epicenter: 33.95 N., 118.72 W. Depth: 11 km Magnitude: 3.4ML(P) Intensity V; West Los Angeles some glassware was broken, few small objects were overturned and fell, trees and bushes were slightly shaken, felt by several. Intensity IV; Agoura. Intensity III; El Monte, Hawthorne, North Hollywood, Thousand Oaks, Paramount, Palms.

4 August (B) Central California Origin time: 15 41 31.5 Epicenter: 38.92 N., 122.67 W. Depth: 6 km Magnitude: 3.0ML(B) 10 16 41.5 36.89 N., 121.49 W. 10 km 3.5ML(B)

11 25 50.9 33.83 N., 117.83 W. 8 km 3.0ML(P)

22 45 24.3 40.00 N., 122.61 W. 13 km 3.7ML(B)

Intensity V; Clear Lake Oaks a few small objects fell and a few windows were cracked. Intensity IV: Clear Lake Highlands. Intensity III; Middletown. Felt; Lakeport (B).

5 August (P) Southern California Origin time: 04 02 19.8 Epicenter: 33.27 N., 116.42 W. Depth: 3 km Magnitude: 3.5ML(P)

Felt at Borrego Springs (P).

5 August (B) Owens Valley area Origin time: 15 38 31.0 Epicenter: 37.63 N., 118.91 W. Depth: 1 km Magnitude: 3.4ML(B), 3.2ML(P)

Felt at Mammoth Lakes (B).

10 August (B) Central California Origin time: 02 11 29.8 Epicenter: 36.59 N., 121.24 W. Depth: 7 km Magnitude: 3.9mb(G), 4.5ML(B) Intensity IV; Felton, Gonzales, Hollister, Monterey, Pacific Grove, Soledad. Intensity III; Big Sur, Boulder Creek, Castroville, Carmel Valley, Coalinga, Mount Herman, Paicines, Moss Landing, Salinas, San Juan Bautista, Sequel. Felt; Watsonville (B).

10 August (B) Central California Origin time: 02 24 00.3 Epicenter: 36.60 N., 121.26 W. Depth: 6 km Magnitude: 3.4ML(B) Intensity III; Salinas (press report). Felt; Hollister (B).

10 August (P) Imperial Valley area Origin time: 18 37 04.2 Epicenter: 32.92 N., 115.53 W. Depth: 15 km Magnitude: 3.6ML(P) Intensity IV; Brawley (press report), El Centre, Imperial, Jacumba (a pan of boiling water slid from a stove and scalded a child), Seeley. Intensity III; Heber.

11 August (B) Central California Origin time: 07 46 43.2 Epicenter: 36.63 N., 121.31 W.

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24 August (B) Central California 28 August (B) Central California Origin time: Epicenter: Depth: Magnitude: Intensity V;

San Jose few small objects were over-

San Jose (Cambrian Park) few windows were

Intensity IV; Boulder Creek, Calaveras Reservoir Dam (press report), Mount Hamilton, Mountain View (press report), San Rafael, Milipitas, Santa Clara, Sunnyvale (press report). Intensity III: Agnew, Belmont, Campbell, Fremont (press report), Half Moon Bay, Mission, San Jose (Saint James Park). Intensity II: Ben Lomond, Felton, turned or fell, some glassware was broken, few merchandise items were thrown from store shelves.

cracked, some glassware was broken, few small objects were overturned or fell. 22 33 36.8 37.46 N., 121.82 W. 6 km 3.9ML(B) Intensity IV; Santa Ana. Intensity III; El Toro Marine Corps Air Station, Perry, Whittier. Intensity II: Glendora.

Origin time: Epicenter: Depth: Magnitude: Intensity V;

San Ramon few merchandise items were thrown from store shelves , some glassware was broken, few small objects were overturned or fell. Stockton few windows were cracked, some glassware was broken, few small objects were overturned or fell, hanging pictures were swung out of place. Intensity IV; Alamo. Intensity III: Alameda, Boulder Creek, Brentwood (press report), Fremont, Hayward, Holt, Livermore (press report), Novato, Volcano. Intensity II; Byron, Elk Grove. Felt: Antioch (B), Dublin (B), Lafayette ~ 01 03 11.3 37.85 N., 121.76 W. 12 km 3.8ML(B) CAL IF ORNI A Cont inued

29 August (B) Owens Valley area Origin time: 05 02 34.8 Epicenter: 37.37 N. , 118.46 W. Depth: 16 km Magnitude: 3.7ML(B), 3.1ML(P) Intensity IV: Bishop.

31 August (B) Central California Origin time: 03 11 07.8 Epicenter: 36.64 N., 121.33 W. Depth: 7 km Magnitude: 4.0ML(B)

Felt at Hollister (B) .

3 September (P) Southern California Origin time: 11 11 06.1 Epicenter: 33.27 N. , 116.42 N. Depth: 4 km Magnitude: 2.6ML(P)

Felt at Borrego Springs (P).

3 September (B) Northern California Origin time: 18 58 24.4 Epicenter: 39.63 N. , 122.52 W. Depth: 9 km Magnitude: 4.3mb(G), 4.0ML(B) Intensity IV: Hamilton City (one report of a cracked foundation), Princeton. Intensity III: Paskenta, Tehama.

5 September (P) Imperial Valley area Origin time: 05 21 26.6 Epicenter: 32.93 N. , 115.85 W. Depth: 4 km Magnitude: 3.7mb(G), 4.4ML(P) Intensity IV: Calexico, Plaster City. Intensity III: Agua Caliente Springs (Canebrake Canyon), Heber, Mount Laguna, Ocotillo, Seeley. Intensity II: Boulevard, Niland. Felt: Brawley (P), El Centre (P).

8 September (B) Owens Valley area Origin time: 18 07 05.0 Epicenter: 37.47 N. , 118.87 W. Depth: 6 km Magnitude: 3.5ML(B)

Felt at Mammoth Lakes (B). Felt at Ridgecrest (P). CALIFORNIA Cont inued

8 September (B) Owens Valley area Origin time: 18 42 19.1 Epicenter: 37.50 N. , 118.86 W. Depth: 6 km Magnitude: 3.8ML(B)

Felt at Mammoth Lakes (B) .

11 September (B) Central California Origin time: 11 59 32.4 Epicenter: 37.41 N., 121.77 W. Depth: 8 km Magnitude: 3.1ML(B)

Felt in the epicentral area (B).

11 September (P) Southern California Origin time: 13 55 31.6 Epicenter: 33.80 N. , 118.23 W. Depth: 4 km Magnitude: 2.6ML(P)

Felt at Carson (P) .

12 September (P) Southern California Origin time: 15 55 53.6 Epicenter: 33.80 N., 118.20 W. Depth: 6 km Magnitude: 2.5ML(P)

Felt at Carson (P) .

16 September (G) Northern California Origin time: 10 26 05.9 Epicenter: 40.70 N., 124.06 W. Depth: 17 km Magnitude: 3.0ML(B) Intensity III: Rio Dell.

17 September (P) Southern California Origin time: 10 57 50.3 Epicenter: 33.93 N., 118.32 W. Depth: 14 km Magnitude: 3.3ML(P)

Felt at Burbank, Pasadena, Long Beach, and Los Angeles (P) .

19 September (P) Southern California Origin time: 13 46 00.7 Epicenter: 35.77 N. , 117.73 W. Depth: 5 km Magnitude: 2.8ML(P) 29 September (P) Southern California

29 September (P) Southern California

30 September (P) Southern California

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Felt at Ridgecrest (P).

Origin time: Epicenter: Depth: Magnitude: Intensity IV; Ridgecrest. Intensity III; Cantil, Mountain Mesa.

Origin time: 18 21 01.1 Epicenter: 35.75 N., 117.75 W. Depth: 8 km Magnitude: 4.2ML(P) Intensity V;

Little Lake few merchandise items were thrown from store shelves, few small objects were overturned or fell, moving vehicles rocked slightly. Ridgecrest a brick fence collapsed and a 15-foot tree split (press report).

Origin time: 22 38 10.6 Epicenter: 35.75 N., 117.75 W. Depth: 8 km Magnitude: 4.4mb(G), 4.1ML(P), 4.4ML(B) 10 43 51.4 35.75 N., 117.75 W. 5 km 3.5ML(P)

18 19 16.1 35.75 N., 117.75 W. 6 km 3.9ML(P)

Intensity V;

Inyokern hairline cracks in plaster walls, hanging pictures out of place Intensity IV: Ridgecrest, Trona. Intensity III: Onyx.

18 September (G) Denver area Origin time: Epicenter: Depth: Magnitude: Intensity III report). Intensity II: Denver (Western Hills).

24 September (K) Eastern Tennessee Origin time: 21 57 42.4

See Tennessee listing.

24 September (K) Eastern Tennessee Origin time: 22 19 16.9

See Tennessee listing.

6 July (H) Island of Hawaii Origin time: Epicenter: Depth: Magni tude: Intensity III; Pahala.

18 July (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III:

8 August (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III; Hilo COLORADO

16 11 44.9 39.90 N., 104.91 W. 5 km 2.8ML(G), 2.8Mn(T) Northglenn, Thornton (press

07 19 02.4 19.29 N., 155.38 W, 6 km 3.2ML(H)

13 30 11.1 19.12 N, 155.52 W. 13 km 3.0ML(H) Discovery Harbor, Pahala

00 02 26.8 19.33 N., 155.19 W 10 km 3.4ML(H)

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10 August (H) Island of Hawaii

10 August (H) Island of Hawaii

12 August (H) Island of Hawaii

12 August (H) Island of Hawaii

20 August (H) Island of Hawaii

20 August (H) Island of Hawaii

27 August (H) Island of Hawaii

11 September (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III:

Origin time: Epicenter: Depth: Magnitude: Intensity III:

Origin time: Epicenter: Depth: Magnitude: Intensity IV; Glenwood, Hilo, Pahala,

Origin time : Epicenter : Depth: Magnitude: Intensity III:

Origin time: Epicenter: Depth: Magnitude: Intensity IV; Kona.

Origin time: Epicenter: Depth: Magnitude: Intensity III; Kona.

Origin time: 11 48 30.7 Epicenter: 20.20 N., 155.64 W. Depth: 10 km Magnitude: 3.8ML(H) Intensity IV: Kohala.

Origin time: Epicenter: Depth: Magnitude: Intensity III; Glenwood. Felt; Ka'u area (press report), Volcano (press report). 11 21 54.1 19.30 N., 155.22 W. 10 km 3.6ML(H) Glenwood, Hilo.

11 37 51.4 19.31 N., 155.22 W. 8 km 3.4ML(H) Hilo.

10 43 35.8 19.42 N., 155.27 W. 16 km 4.0ML(H)

12 44 04.5 W 19.42 N., 155.27 16 km 3.3ML(H) Hilo.

08 51 20.5 19.75 N. , 156.03 W 8 km 3.6ML(H)

08 59 59.1 19.75 N., 156.01 W 8 km 3.0ML(H)

05 03 44.7 19.39 N., 155.42 W. 11 km 3.4ML(H) HAWAII continued

12 September (H) Island of Hawaii Origin time: 16 18 34.6 Epicenter: 19.36 N. , 155.00 W. Depth: 9 km Magnitude: 3.1ML(H) Intensity III: Kalapana. Felt: Hilo (press report), Puna area (.press report) .

14 September (H) Island of Hawaii Origin time: 19 17 32.6 Epicenter: 19.18 N., 155.60 W. Depth: 10 km Magnitude: 3.6ML(H) Intensity IV: Pahala . Intensity III: Hawaiian Ocean View Estates.

22 September (H) Island of Hawaii Origin time: 01 35 27.8 Epicenter: 19.33 N. , 155.12 W. Depth: 9 km Magnitude: 3.7ML(H) Intensity IV: Hilo.

24 September (H) Island of Hawaii Origin time: 00 23 37.5 Epicenter: 19.38 N. , 155.40 W. Depth: 11 km Magnitude: 3.2ML(H) Intensity III: Pahala.

26 September (H) Island of Hawaii Origin time: 03 02 15.1 Epicenter: 19.39 N. , 155.28 W. Depth: 6 km Magnitude: 3.3ML(H) Intensity III: Volcano.

26 September (H) Island of Hawaii Origin time: 04 38 47.3 Epicenter: 19.40 N., 155.26 W. Depth: 1 km Magnitude: 3.3ML(H) Intensity III: Volcano.

29 September (H) Island of Hawaii Origin time: 16 20 52.1 Epicenter: 19.37 N., 155.18 W. Depth: 32 km Magnitude: 3.4ML(H)

C25

10 August (G) Central Idaho

30 September (G) Eastern Idaho

11 August (S) Southern Illinois

11 July (G) Eastern South Dakota

11 July (G) Eastern South Dakota

3 July (K) New Madrid Region

13 July (K) New Madrid region Origin time: 19 35 46.2 Epicenter: 44.62 N., 114.40 W Depth: 5 km Magnitude: 4.1ML(G), 3.5ML(D) Intensity III: Lemhi.

Origin time: 02 27 19.8 Epicenter: 42.64 N. , 111.46 W. Depth: 5 km Magnitude: 3.5ML(G) Intensity III: Etna, Wyoming.

Origin time: 10 32 38.8 Epicenter: 37.25 N., 88.73 W. Depth: 5 km Magnitude: 3.0Mn(G), 2.9MD(K) Intensity III: Metropolis.

Origin time: 19 42 28.4

See South Dakota listing.

Origin time: 19 42 28.4

See South Dakota listing.

Origin time: 04 58 48.8 Epicenter: 36.58 N., 89.99 W. Depth: 9 km Magnitude: 2.7MD(K)

Felt near Maiden (K).

Origin time: 04 30 52.7 IDAHO

MISSOURI 5 August (G) Northwestern Montana Origin time: 01 48 16.5 Epicenter: 47.85 N., 114.35 W. Depth: 5 km Magnitude: 2.5ML(G), 2.4MD(D)

Felt in the Echo Lake area, Ferndale, and along the east shore of Flathead Lake (D)

8 August (G) Northwestern Montana Origin time: 07 48 07.4 Epicenter: Depth: Magnitude:

Felt at Bigfork and in Echo Lake area (D).

8 August (G) Northwestern Montana Origin time: 07 49 23.1 Epicenter: 47.93 N., 114.34 W. Depth: 5 km Magnitude: 2.8ML(G), 2.7ML(D)

Felt at Kalispell and in the area north of Flathead Lake (D).

8 August Northwestern Montana Origin time: Epicenter: Depth: Magnitude: Intensity IV;

8 August Northwestern Montana Origin time: Epicenter: Depth: Magnitude: Intensity IV:

6 July (G) Southern Nevada Origin time: 02 10 43.5 Epicenter: 37.69 N., 115.05 W, 12 km 2.6Mn(G), 2.4MD(K)

47.93 N., 114.36 W.

5 km 2.3MD(D)

05 15 Not located None computed None computed Marion.

09 45 Not located None computed None computed Marion.

C26

29 July (E) Southern Nevada

5 August (E) Southern Nevada

11 August (E) Southern Nevada

29 August (B) California-Nevada border region

2 September (E) Southern Nevada

23 September (E) Southern Nevada Depth: Magnitude:

Intensity III;

Origin time: 20 05 00.083 Epicenter: 37.10 N., 116.08 W. Depth: 0 km Magnitude: 4.5mb(G), 4.6ML(B)

Nevada Test Site explosion "MONTEREY" at 37°06'08.30" N., 116°04'29.90" W.,.surface elevation 1280 m, depth of burial 400 m.

Origin time: 14 00 00.090 Epicenter: 37.08 N., 116.01 W. Depth: 0 km Magnitude: 5.7mb(G), 4.2MS(G), 5.4ML(B)

Nevada Test Site explosion "ATRISCO" at 37 0 05'03.14" N., 116°00'23 .57" W., surface elevation 1295 m, depth of burial 640 m.

Origin time: 15 00 00.000 Epicenter: 37.19N., 116.05 W. Depth: 0 km Magnitude: 3.3ML(G)

Nevada Test Site explosion "QUESO" at 37°11'23.25" N., 116°02'51.66" W., surface elevation 1337 m, depth of burial 216 m.

Origin time: 21 08 04.0 Epicenter: 38.17 N., 118.43 W. Depth: 5 km Magnitude: 4.0ML(B), 3.9ML(P)

Felt in the epicentral area (B).

Origin time: Epicenter: Depth: Magnitude:

Nevada Test Site explosion "CERRO" at 37°0ril.04" N., 116 0 00'56.41" W., surface elevation 1212 m, depth of burial 229 m.

Origin time: 16 00 00.091 Epicenter: 37.21 N., 116.21 W. 3 km 4.1mb(G), 4.2ML(G), 4.7ML(B) Hiko.

5.6ML(P)

14 00 00.090 37.02 N., 116.02 W. 0 km 3.3ML(G) Origin time: Epicenter: Depth: Magnitude:

Nevada Test Site explosion "FRISCO" at 37°10'29.10" N., 116°05'16.06" W., surface elevation 1374 m, depth of burial 451 m.

24 September (B) California-Nevada border region Origin time: 07 40 24.3 Epicenter: 37.85 N., 118.12 W. Depth: 5 km Magnitude: 5.0mb(G), 4.6MS(G), 5.4ML(B) 17 00 00.082 37.18 N., 116.09 W. 0 km 4.9mb(G), 4.8ML(B)

29 September (E) Southern Nevada

20 September (G) Southern New Mexico

C27

Dyer (Fish Lake Valley) few merchandise items were thrown from store shelves, few small objects were overturned or fell, hanging pictures fell, felt by all. Montgomery Pass area objects were knocked off shelves, a house trailer shifted on its foundation. Yerington knocked objects off shelves. Intensity IV;

California Auberry, Benton, Bridgeport, June Lake, Lakeshore, Lee Vining, Lone Pine, Mammoth Lakes, Wishon. Nevada Hawthorne, Luning, Mina, Schurz. Intensity III;

California Big Creek, Friant, Murphys, Topaz. Nevada Carson City, Gabbs, Smith, Tonopah. Intensity II;

California Shaver Lake, Three Rivers Nevada Reno, Wellington Felt:

California Bass Lake, Big Pine, Orange Cove.

Origin time: Epicenter: Depth: Magnitude:

Nevada Test Site explosion "BORREGO" at 37°05'28.69" N., 116°02'41.59" W., surface elevation 1261 m, depth of burial 564 m.

Origin time: 03 55 17.2 Epicenter: 33.95 N., 107.06 W. Depth: 11 km 13 30 00.096 37.09 N., 116.05 W. 0 km 4.1ML(B)

NEW MEXICO 31 August (L) Eastern New York Origin time: Epicenter: Depth: Magnitude: Intensity III; Northville (press report)

24 September (K) Eastern Tennessee Origin time: 21 57 42.4

See Tennessee listing.

24 September (K) Eastern Tennessee Origin time: 22 19 16.9

See Tennessee listing.

16 July (K) Northwestern South Carolina Origin time: Epicenter: Depth: Magnitude: Intensity III:

Phillips areas of Newberry County.

12 August Northwestern South Carolina Origin time: 18 30 Epicenter: Not located Depth: None computed Magnitude: 2.0Mn (University of

Intensity III: Newberry (press report)

11 July (G) Eastern South Dakota Origin time: 19 42 28.4 Epicenter: 44.01 N., 96.72 W. Depth: 5 km Magnitude: 3.6Mn(T)

10 16 58.1 43.21 N., 74.20 W. 4 km 2.7Mn(L)

14 16 01.8 34.28 N., 81.51 W. 7 km 3.1MD(K) Keitts Crossroads and St

South Carolina)

C28

14 July (K) Northwestern Tennessee

5 September (K) Eastern Tennessee

24 September (K) Eastern Tennessee Intensity V;

South Dakota Brandon a few small objects were overturned and fell, hanging pictures were swung out of place, buildings shook strongly, felt by all and frightened many. Chester a few items were thrown from store shelves, buildings shook strongly, felt by all and frightened many. Renner a few windows were cracked, vibration was described as "strong," felt by many. Sherman some glassware was broken, a few small objects were overturned and fell, trees and bushes were slightly shaken. Intensity IV:

Iowa Brunsville, George.

Minnesota Chandler, Hills, Luverne, Pipes tone. South Dakota Colman, Colton, Corson, Flandreau, Garretson, Lyons, Nunda, Rutland, Trent, Ward, Wentworth. Intensity III;

Iowa Matlock, Sioux Center.

Minnesota Beaver Creek, Clarkfield, Edgerton, Holland, Rushmore, Verdi. South Dakota Baltic (press report), Dell Rapids (press report), Egan, Elkton, Humboldt, Jasper, Lennox, Madison, Ramona, Sinai, Sioux Falls (press report), Valley Springs, Volga.

Origin time: 16 01 35.6 Epicenter: 36.26 N., 89.45 W. Depth: 4 km Magnitude: 2.4MD(K)

Felt in the Ridgely area (K).

Origin time: Epicenter: Depth: Magnitude: Intensity IV: Benton, Delano, Reliance, Intensity III: Etowah.

Origin time: 21 57 42.4 Epicenter: 35.68 N., 84.24 W. TENNESSEE

10 11 09.4 35.20 N., 84.51 W. 13 km 3.2MD(K), 2.8Mn(G)

Depth:

Magnitude:

Intensity V;

Intensity IV:

North Carolina Fontana Dam.

Intensity III;

Georgia McCaysville.

North Carolina Hayesville.

Tennessee Etowah, Turtletown.

Intensity II;

Georgia Crandall.

Tennessee Ducktown, Jefferson City, Mon-

Felt;

Tennessee Concord, Townsend.

24 September (K) Eastern Tennessee Origin time: Epicenter: Depth: Magnitude: Intensity IV:

North Carolina Alcoa, Fontana Dam.

Tennessee Delano, Friendsville, Loudon,

Intensity III:

Georgia Cherry Log, McCaysville.

Tennessee Etowah, Knoxville.

Intensity II:

Georgia Crandall.

Tennessee-Ducktown.

29 September (K) Northwestern Tennessee Origin time; Epicenter: Depth: Magnitude:

Felt in the Ridgely area (K).

29 September (K) Northwestern Tennessee Origin time: 02 06 28.0 Epicenter: 36.26 N., 89.43 W. Alcoa a few dishes were broken and a few small objects fell. Knoxville a few windows were cracked, some glassware was broken, and a few small objects were overturned or fell. Mount Vernon a few small objects were overturned, felt by all. Tallassee some glassware was broken, a few small objects were overturned or fell, well water was muddied.

Greenback, Grimsley, Lenoir City, Loudon, Madisonville, Seymour, Sweetwater, Tellico Plains, Ten Mile, Vonore.

terey, Petros.

Lenoir City, Madisonville, Maryville, Mount Vernon, Reliance, Sweetwater, Tellico Plains, Ten Mile, Vonore. 14 km 3.0Mn(V), 3.2MD(K)

22 19 16.9 35.69 N., 84.25 W. 10 km 3.4Mn(V), 3.4MD(K)

02 05 56.3 36.24 N., 89.42 W. 9 km 2.0MD(K)

C29

15 July (W) Central Washington

15 September (W) Puget Sound area

26 September (W) Central Washington

31 August (G) Central Wyoming

30 September (G) Eastern Idaho Depth: Magnitude:

Felt at Ridgely (K)

Origin time: Epicenter: Depth: Magnitude: Intensity III:

Origin time: Epicenter: Depth: Magnitude: Intensity IV; Duvall (W).

Origin time: Epicenter: Depth: Magnitude:

Felt in the Naches area (W).

Origin time: Epicenter: Depth: Magnitude: Intensity III:

Origin time: 22 02 18.5 Epicenter: 42.72 N., 108.85 W. Depth: 5 km Magnitude: 3.2ML(G)

The effects at Ethete were reported as sounding like a sonic boom, only louder and longer, with no accompanying vibration.

Intensity IV; Lander.

Origin time: 02 27 19.8

See Idaho listing. 7 km 2.8MD(K)

03 02 07.5 47.25 N., 119.95 W. 1 km 2.4MD(W) Quincy (W).

17 32 33.2 47.69 N., 122.03 W, 7 km 2.9MD(W)

10 09 23.9 46.87 N., 121.07 W. 4 km 2.9ML(G), 3.4MD(W)

01 19 54.8 44.19 N., 110.90 W. 5 km 3.0ML(G) Grant Village, Old Faithful,

ACKNOWLEDGMENTS

Listed below are the collaborators who furnished data to the U. S. Geological Survey for use in this circular:

ALASKA: Staff of National Oceanic and

CALIFORNIA: Clarence R. Alien, Seismological

Bruce A. Bolt, Seismograph Sta-

HAWAII: Robert Y. Koyanagi, U.S. Geologi-

MASSACHUSETTS: Staff of Weston Observatory, Bos-

MISSOURI: Robert Hermann and Otto Nuttli,

MONTANA: Anthony Qamar, University of Mon-

NEW YORK: Lynn R. Sykes and Alan L. Kafka,

OKLAHOMA: James E. Lawson, Jr., Oklahoma Atmospheric Administration, Alaska Tsunami Warning Center, Palmer.

Laboratory, California Institute of Technology, Pasadena.

tion, University of California, Berkeley.

cal Survey, Hawaiian Volcano Observatory, Hawaii National Park.

ton College, Weston.

Department of Geology and Geophysics, St. Louis University, St. Louis.

tana, Missoula.

Lament-Doherty Geological Observatory, Columbia University, Palisades.

Geophysical Observatory, Oklahoma Geological Survey, Leonard.

C30

TENNESSEE: A. Johnson, Tennessee Earthquake

UTAH: Department of Geology and Geophy-

VIRGINIA: G. A. Bollinger, Department of

WASHINGTON: Robert S. Crosson, Geophysics

Bath, Markus, 1966, Earthquake energy and magni-

Gutenberg, B. and Richter, C. F., 1956, Magni-

Nuttli, 0. W., 1973, Seismic wave attenuation

Richter, C. F., 1958, Elementary seismology:

Wood, H. 0. and Neumann, F., 1931, Modified Mer-

REFERENCES CITED

tude, in Physics and chemistry of the Earth, Volume 7: Oxford and New York, Pergamon Press, p. 115-165.

tude and energy of earthquakes: Annali di Geofisica, v. 9, no. 1, p. 1-15.

and magnitude relations for eastern North America: Journal of Geophysical Research, v. 78, no. 5, p. 876-885.

San Francisco, W. H. Freeman, 768 p.

calli Intensity Scale of 1931: Seismological Society of America Bulletin, v. 21, no.

4, p. 277-283.

Information Center, Memphis State University, Memphis.

sics, University of Utah, Salt Lake City.

Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg.

Program, University of Washington, Seattle.

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