Earthquakes in the United States, October-December 1981

JAMES G. WATT, Secretary

Geological Survey

Dallas L. Peck, Director

Introduction................................................................. Dl

Discussion of tables••••••••••••••••••••••••••••••••••••••••••••••••••••••••• Modified Mercalli Intensity Scale of 1931....................................

ILLUSTRATIONS

1. "Earthquake Report" form••••••••••••••••••••••••••••••••••••••••••
2. Map showing standard time zones of the conterminous United States.
3. Map showing standard time zones of Alaska and Hawaii ••••••••••••••
4. Map of earthquake epicenters in the conterminous United States for October-December 1981.............................................
5. Map of earthquake epicenters in Alaska for October-December 1981..
6. Map of earthquake epicenters in Hawaii for October-December 1981..
7. Intensity map for the southern California earthquake
8. Intensity map for the Long Island Sound, New York, earthquake of

21 October 1981................................................... 24

iii

iv

The earthquake information in this publication supplements that published by the U. S. Geological Survey (USGS) in the National Earthquake Information Service (NElS) 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 power plant site evaluations, seismicity studies, and to answer inquiries by the public.

This publication contains two major sections. 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 two maps and table 2. This section also contains 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 suspected explosions are also listed in table and table 2.

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

INTRODUCTION

The first part (table 1), which is

Dl

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. 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. Report" forms are mailed to postmasters within the area affected by the earthquake. pleted forms are returned to the USGS, where they are evaluated and intensity values are assigned to individual locations. In the case of large or significant earthquakes, the intensity observations are plotted and isoseismal maps are prepared. It should be pointed out that the isoseismals represent a general intensity level and that they do not necessarily agree with every individual observation.

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. taken from those published in the PDE, or from other sources as noted, are listed here to two Copies of the current "Earthquake

The USGS uses the postal questionnaire as

DISCUSSION OF TABLES

The parameters for the earthquakes in table

The epicenters, which were FIGURE I.--Example of the "Earthquake Report" form used for evaluating the intensities of earthquakes. !, front side. FIGURE 1.--Example of the "Earthquake Report" form used for evaluating the intensities of earthquakes. !, reverse side.

D3

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.)

decimals. The accuracy of the epicenters is not necessarily indicated by the number of decimals listed. The epicenters located by the NElS 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 October-December 1981. The magnitudes represented in these figures are based on ML, Mn, or MD; if neither was 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 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:

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°(D(160°. No depth correction is made for depths less than 50 km.

as defined by Gutenberg and Richter (1956), except that T, the period in seconds, is restricted to 0.1(T(3.0, and A, the ground amplitude in micrometers, is not necessarily the maximum of the P-wave group. Q is a function of distanceD and depth h, where D25°.

a-.

FIGURE 4.--Earthquake epicenters in the conterminous United States for October-December 1981, plotted from table 1.

Depth -· 50 <70 km ~70 km Magnitude <5.0 Magnitude 5.0-5.9

EXPLANATION

FIGURE 5.--Earthquake epicenters in Alaska for October-December 1981, plotted from table 1.

MODIFIED MERCALLI INTENSITY SCALE OF 1931 --------------------------------------------------------------------------------------------------------------------· ------------ -------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------

DEC.

OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. 11 OCT. 13 OCT. 13 OCT. 14 OCT. 14 OCT. 15 OCT. 16 OCT. 16 OCT. 16 OCT. 16 OCT. 16 OCT. 18 OCT. 18 OCT. 18 OCT. 18 OCT. 18 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 19 OCT. 22 OCT. 24 OCT. 24 OCT. 24 OCT. 24 OCT. 25 OCT. 25 OCT. 26 OCT. 26 OCT. 28 OCT. 30 OCT. 31 NOV. NOV. 03 29 34.5

15 12 19.6 08 13 23.0 04 16 04.4 12 03 03.5 11 17 30.5 13 05 24.2 07 40 13.1 19 44 59.4 02 08 35.5 01 16 12.3 07 58 08.9 09 19 48.6 19 23 59.4 03 33 19.7 00 37 58.1 09 27 23.9 11 03 19.6 13 59 36.3 21 36 28.1 07 52 50.4 11 22 49.2 14 36 34.4 14 43 21.3 17 39 00.1 10 41 31.2 12 36 47.5 14 57 31.7 15 44 50.4 19 31 40.0 01 46 16.0 03 53 27.8 04 35 45.3 07 06 58.3 08 02 19.6 09 32 58.6 14 28 37.0 15 00 18.0 15 09 57.6 15 49 44.4 20 22 17.4 04 50 14.0 07 01 31.6 08 11 17.9 20 00 32.2 00 56 45.2 12 19 14.1 02 37 02.1 09 26 00.2 03 56 08.2 04 42 13.7 06 44 13.8 06 37 39.7 12 18 58.0 ALABAMA 33.24 N. 87.02 w.

ALASKA 67.90 N. 161.88 w. 33 61.54 N. 149.91 w. 52 52.60 N. 170.67 vl. 46 59.15 N. 152.90 w. 113 51.87 N. 176.57 w. 88 62.17 N. 151.08 w. 105 51.45 N. 175.72 E. 23 63.58 N. 149.96 w. 28 60.11 N. 141.06 w. 15 61.84 N. 148.86 w. 26 58.38 N. 151.29 w. 33 52.30 N. 173.59 w. 68 61.96 N. 147.25 w. 65 60.84 N. 150.94 w. 33 53.82 N. 167.34 w. 111 58.46 N. 155.12 w. 121 60.36 N. 152.08 w. 120 67.84 N. 162.06 w. 15 57.75 N. 150.92 w. 150 60.91 N. 147.01 w. 33 60.23 N. 140.92 w. 15 60.21 N. 140.98 w. 15 60.26 N. 140.98 w. 15 60.21 N. 140.94 w. 15 67.93 N. 161.93 w. 15 60.37 N. 151.64 w. 90 67.83 N. 161.76 w. 15 67.93 N. 161.91 w. 15 67.81 N. 161.88 w. 15 60.24 N. 152.34 w. 127 67.88 N. 161.65 w. 15 67.80 N. 161.68 w. 15 67.58 N. 161.45 w. 15 67.89 N. 161.75 w. 15 67.84 N. 161.89 w. 15 67.79 N. 161.50 w. 15 68.00 N. 161.93 w. 15 67.98 N. 161.69 w. 15 65.87 N. 156.21 w. 33 51.33 N. 176.82 w. 41 61.53 N. 150.61 w. 33 51.31 N. 173.06 w. 33 51.82 N. 173.23 w. 41 60.65 N. 150.40 w. 53 57.66 N. 153.16 w. 64 52.59 N. 169.59 w. 51 59.67 N. 152.66 w. 108 63.55 N. 149.99 w. 33 63.10 N. 149.45 w. 104 64.76 N. 160.55 w. 33 53.00 N. 163.87 w. 33 52.02 N. 170.42 E. 33 61.70 N. 150.68 w. 57

------------------- intensity

S:iM 4.4M 3.9}1 3.1M

4:2H

4.5M 3.7M 4.5M 3.8}1 3.9M

4.1M 2.9M 3.0M 3.3M 3.4M 4.3M 3.6M 3.9M 4.2M

3.2M 3.9M 4.4M 4.5M

3:7M 3.2M 4.5M 3:2M

K DEC.

G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G OCT. G NOV.

8 09 P.M. CST

1 04 A.M. BST 1 10 P.M. AST 2 05 P.M. BST 3 02 A.M. AST 4 00 A.M. BST 5 03 A.H. AST 5 08 P.M. BST 6 09 A.H. AST 6 04 P.M. AST 7 03 P.M. AST 7 09 P.M. AST 8 10 P.M. BST 9 09 A.M. AST 10 05 P.M. AST 12 01 P.M. BST 12 11 P.M. AST 14 01 A.M. AST 14 02 A.M. BST 15 11 A.M. AST 15 09 P.M. AST 16 02 A.M. YST 16 05 A.M. YST 16 05 A.H. YST 16 08 A.M. YST 17 11 P.M. BST 18 02 A.M. AST 18 03 A.M. BST 18 04 A.M. BST 18 08 A.M. BST 18 03 P.M. AST 18 04 P.M. BST 18 05 P.M. BST 18 08 P.M. BST 18 09 P.M. BST 18 10 P.M. BST 19 03 A.M. BST 19 04 A.M. BST 19 04 A.M. BST 19 05 A.M. AST 22 09 A.M. BST 23 06 P.M. AST 23 08 P.M. BST 23 09 P.M. BST 24 10 A.M. AST 24 02 P.M. AST 25 01 A.H. BST 25 04 p .l-'1. AST 25 11 P.M. AST 27 05 P.M. AST 29 06 P.M. -AST 30 07 P.M. BST 31 07 P.M. BST 2 02 A.M. AST NOV. NOV. NOV. NOV. NOV. NOV. NOV. NOV. NOV. NOV. 10 NOV. 13 NOV. 13 NOV. 13 NOV. 14 NOV. 15 NOV. 15 NOV. 16 NOV. 16 NOV. 17 NOV. 18 NOV. 18 NOV. 18 NOV. 19 NOV. 19 NOV. 22 NOV. 22 NOV. 23 NOV. 25 NOV. 29 NOV. 29 NOV. 30 NOV. 30 NOV. 30 DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. 10 DEC. 10 DEC. 11 DEC. 13 DEC. 14 DEC. 14 DEC. 15 DEC. 16 DEC. 17 DEC. 18 DEC. 20 DEC. 20 DEC. 22 DEC. 24 DEC. 25 DEC. 28 DEC. 28 DEC. 30 DEC. 30 02 42 02.9 05 25 01.9 23 17 47.1 19 46 56.2

22 36 24.0 00 07 52.8 04 59 34.7 16 45 06.0 03 07 16.1 10 03 01.1 12 12 59.7 18 10 29.3 00 43 03.3 18 49 08.0 21 05 55.7 06 47 57.0 23 49 48.0 11 28 40.8 06 16 08.5 11 19 14.1 19 34 46.7 01 45 33.7 04 20 07.6 12 51 17 0 3 17 55 06.6 07 27 34.6 02 43 41.2 05 18 18.9 22 27 54.5 01 14 45.8 04 29 30.8 14 48 35.9 20 OS 09.3 13 51 02.9 OS 45 00.4 04 41 48.0 17 27 41.6 14 42 58.1 17 45 40.1 14 06 59.0 18 04 40.9 12 22 17.6 02 26 23.6 OS 45 16.1 06 43 41.4 03 46 53.1 09 17 35.0 21 13 10.8 21 34 52.4 08 06 33.3 00 34 42.9 14 20 45.5 10 52 06.4 14 13 47.3 04 31 34.6 01 08 24.4 22 26 38.6 10 28 16.1 22 01 50.1 08 09 44.1 13 31 50.7 67.98 N. 51.99 N. 63.01 N. 67.56 N. 51.73 N. 51.79 N. 58.23 N. 64.27 N. 53.22 N. 52.39 N. 60.61 N. 52.64 N. 60.13 N. 54.07 N. 67.93 N. 68.00 N. 51.75 N. 60.11 N. 60.31 N. 64.58 N. 62.25 N. 53.81 N. 61.40 N. 52.57 N. 63.04 N. 60.86 N. 60.69 N. 52.52 N. 65.81 N. 63.08 N. 58.32 N. 63.41 N. 60.20 N. 51.04 N. 62.91 N. 63.44 N. 60.02 N. 61.97 N. 57.35 N. 61.90 N. 64.83 N. 62.77 N. 53.19 N. 51.88 N. 63.17 N. 60.86 N. 62.80 N. 62.51 N. 59.95 N. 65.65 N. 65.54 N. 65.82 N. 61.29 N. 61.27 N. 59.97 N. 59.96 N. 63.99 N. 59.65 N. 54.67 N. 63.11 N. 52.39 N. 64.50 N. ALASKA--Continued

159.38 w. 33 170.92 W'. 41 150.54 w0 110 161.55 w. 15 174.28 w. 33 174.41 w. 33 155.10 w. 129 149.43 w. 33 165.75 w. 33 169.38 w. 41 147.21 w. 33 168.63 w. 33 150.73 w. 79 164.54 w0 66 161.77 w. 15 161.85 w. 15 174.38 w. 33 153.12 w. 126 151.74 w. 74 149.21 w. 10 149.16 w. 73 163.90 w. 60 149 0 96 w. 45 172.56 E. 39 150.84 w. 143 150.61 -J. 85 151.19 w. 86 173.17 w. 33 145.16 w. 33 148.54 w. 107 151.68 w0 33 150.36 w0 150 147.84 w. 33 178.87 E. 42 148 0 7 5 w. 93 150.39 w0 126 153.35 w. 137 148.40 w. 63 152.26 w. 33 147.65 w. 33 147.49 w. 15 151.06 w. 33 154.83 w0 33 179.72 E. 109 150.75 w. 161 148.09 w. 33 149.03 w. 88 152.56 w. 158 153.93 w. 198 154.25 w0 33 150.05 w. 33 155.06 w. 33 150.20 w. 33 150.30 w. 65 152.93 w. 122 152.84 w. 125 148.88 w. 33 152.81 w. 107 160.41 w0 33 150.82 w. 151 169.59 w. 45 147.96 w. 15

4:iM

2.9M FELT 3.0M 3.1M 4.9M

3.5M 3.4M 2.6M 2.1M

3:sM

G NOV.

G NOV.

G NOV.

G NOV.

G NOV.

G NOV.

G NOV.

G NOV.

G NOV.

IV G NOV. G NOV. G NOV. G NOV. III G NOV. G NOV. G NOV. G NOV. G NOV. II IV G NOV. IV G NOV. G NOV. G NOV. G NOV. III G NOV. G NOV. G NOV. G NOV. III G NOV. G NOV. G NOV. G NOV. G NOV. G NOV. G DEC. G DEC. G DEC. G DEC. G DEC. IV G DEC. G DEC. G DEC. III G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. G DEC. III G DEC. III G DEC. G DEC • G DEC. G DEC. G DEC. G DEC. G DEC. G DEC.

3 04 P.M. AST 3 06 P.M. BST 4 01 P.M. AST 5 08 A.M. BST 8 00 A.N. BST 8 11 A.M. BST 8 02 P.M. AST 8 06 P.M. AST 9 05 A.M. BST 9 04 P.M. BST 13 00 A.M. AST 13 01 A.M. BST 13 08 A.M. AST 13 01 P.M. BST 15 07 A.H. BST 15 10 A.M. BST 15 07 P.M. BST 16 01 P.M. AST 17 01 A.M. AST 17 08 P.H. AST 18 01 A.M. AST 18 08 A.N. BST 18 03 P.H. AST 18 05 P.M. BST 22 02 A.H. AST 22 07 A.M. AST 22 09 P.M. AST 24 03 P.M. BST 28 07 P.M. AST 29 12 P.M. AST 29 03 P.M. AST 29 06 P.N. AST 30 04 A.M. AST 1 09 A.M. BST 4 03 A.M. AST 4 07 P.M. AST 5 06 P.M. AST 6 07 A.M. AST 7 04 A.M. AST 7 07 A.M. AST 8 04 A.M. AST 8 08 A.M. AST 9 02 A.M. AST 9 03 P.M. BST 9 07 P.M. AST 10 08 P.M. AST 12 05 P.M. AST 13 11 P.M. AST 14 11 A.M. AST 15 11 A.N. AST 15 10 P.M. AST 16 02 P.M. AST 18 04 A.M. AST 20 00 A.M. AST 20 04 A.M. AST 21 06 P.M. AST 23 03 P.M. AST 25 12 P.M. AST 28 00 A.M. AST 28 12 P.M. AST 29 09 P.M. BST 30 03 A.M. AST

DEC. 30 DEC. 30 DEC. 30 DEC. 30 DEC. 30 DEC. 30 DEC. 30 DEC. 31

OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. OCT. 10 OCT. 11 OCT. 13 OCT. 13 OCT. 16 OCT. 16 OCT. 17 OCT. 17 OCT. 20 OCT. 20 OCT. 21 OCT. '23 OCT. 23 OCT. 25 OCT. 26 OCT. 28 OCT. 29 OCT. 30 OCT. 31 OCT. 31 NOV. NOV. NOV. NOV. NOV. NOV. 10 NOV. 10 NOV. 10 NOV. 10 NOV. 11 13 38 41.5 13 46 18.1 13 47 26.7 13 59 52.8 14 00 33.5 14 07 58.0 14 11 28.1 12 15 54.5

01 04 15.5 07 02 05.1 09 13 57.4 13 22 36.0 15 00 17.9 18 16 47.2 22 05 07.9 07 37 22.3 07 45 03.0 16 14 23.5 18 18 13.3 01 20 37.3 07 23 32.6 14 40 55.3 00 30 41.2 04 27 36.9 06 32 51.3 17 43 22.4 05 46 12.2 07 16 11.2 23 36 39.0 11 01 00.2 11 17 26.0 17 50 22.1 18 55 28.9 12 13 17.8 18 10 12.6 04 44 48.7 20 14 03.0 04 07 33.4 22 03 16.1 19 47 21.8 19 54 35.0 02 25 20.0 12 40 55.6 05 37 44.7 17 28 16.9 19 15 52.5 17 18 03.3 14 58 01.8 14 17 08.9 12 30 58.8 17 07 25.8 08 59 07.9 23 14 32.7 05 08 05.9 21 33 37.9 11 54 56.1 03 30 17.3 15 54 40.5 07 33 07.3 19 17 48.6 22 34 35.5 22 37 05.0 00 29 44.4 ALASKA----Continued 55.80 N. 157.84 w. 33 64.50 N. 147.96 w. 15 64.51 N. 147.99 w. 15 64.50 N. 147.93 w. 15 64.56 N. 148.09 w. 24 64.50 N. 147.91 w. 15 64.50 N. 147.93 w. 15 61.91 N. 151.76 w. 128

CALIFORNIA 37.63 N. 118.87 w. 37.53 N. 118.89 w. 37.51 N. 118.90 w. 37.62 N. 118.88 w.

37.58 N. 118.83 w. 37.51 N. 118 0 91 w0 5 37.63 N. 118.88 w. 37.64 N. 118.88 w. 37.63 N. 118.87 w. 37.65 N. 118.89 w. 37.60 N. 118.84 w. 37.57 N. 118.83 ~1. 5 37.59 N. 118.89 w. 37.48 N. 118.92 w. 37.61 N. 118.87 w. 37.63 N. 118.89 w. 34.23 N. 117.43 w. 12 37.51 N. 118.92 w. 40.42 N. 123.52 w. 37.58 N. 118.87 w. 37.64 N. 118.89 w. 11 37.58 N. 118.83 w. 37.57 N. 118.83 w. 38.77 N. 122.68 w. 40.52 N. 122.12 w. 33.65 N. 119.05 w. 37.57 N. 118.93 w. 34.03 N. 116.15 w. 33.60 N. 119.02 w. 15 37.54 N. 118.89 w. 27 33.23 N. 116.07 w. 33.23 N. 116.07 w. 37.63 N. 118.86 w. 28 33.52 N. 116.45 w. 33.50 N. 116.77 w. 33.63 N. 119.02 w. 12 33.63 N. 119.05 w. 40.14 N. 124.27 w0 5 37.39 N. 118.53 w. 18 34.33 N. 118.52 w. 40.12 N. 124.33 w. 33.62 N. 119.00 w0 6 38.77 N. 122.71 w. 33.63 N. 119.05 w. 12 33.62 N. 119 •. 00 w. 40.10 N. 124.75 w. 33.90 N. 118.63 w. 37.54 N. 118.88 w. 22 32.83 N. 115.63 w. 37.61 N. 118.94 w0 5 37.62 N. 118.90 w0 12 35.02 N. 119.13 w. 35.02 N. 119.18 w0 9 35.02 N. 119.17 w.

------------------- intrnsity

3.5B FELT 4.6B FELT 3.5B 3.7B FELT 3.4B 3.2B 3.4B FELT 4.2B 3.1B 3.5B FELT 3.4B 4.0B FELT 3 .1B 3.7B FELT 3 .1B 3.0B 3.3B 3.0P 3.1B 2.7B 3.0B 3.6B FELT 3.6B FELT 3.2B 3.2B FELT 3.2B FELT 3.6P 3.0B 3.3P 3.2P 3.2B 3.8P 3 .1P 3.3B 3.0P 3.6P FELT 4.6P 4.6P 3.8B 3 .1B 3 .1P 3.3B 3.6P 3.0B 3.1P 3.0P 3.1B 2.7P FELT 3.5B 2.7P 3.1B 3.4B 4.6P 4.2P FELT 3.4P G DEC. G DEC. IV G DEC. G DEC. G DEC.

v

G DEC.

G DEC.

G DEC.

B SEPT. 30 05 P.M. PST B SEPT. 30 11 p .11. PST B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. IV B OCT. B OCT. B OCT. B OCT. B OCT. B OCT. 10 04 A.M. PST p OCT. B OCT. 12 08 P.M. PST p OCT.

B OCT. 16 02 P.M. PST p OCT. p OCT. B OCT. 19 06 P.M. PST p OCT. IV p OCT. v p OCT. 23 09 A.M. PST v p OCT. A.M. PST B OCT. 25 09 A.M. PST B OCT. 26 06 A.M. PST

iii

III B OCT. p OCT. B OCT. 31 00 A.M. PST

p NOV.

B NOV.

B NOV.

p NOV.

"iv

B NOV.

B NOV. 10 11 A.M. PST p NOV.

v

30 03 A.M. AST 30 03 A.M. AST 30 03 A.M. AST 30 03 A.M. AST 30 04 A.M. AST 30 04 A.M. AST 30 04 A.M. AST 31 02 A.M. AST

OCT.

11 10 A.M. PST OCT. 13 12 P.M. PST 15 08 P.M. PST

17 11 A.M. PST 17 11 A.M. PST 20 04 A.M. PST 20 09 P.M. PST

OCT. 28 06 A.M. PST 29 04 A.M. PST 30 09 A.M. PST OCT. 31 03 P.M. PST

NOV.

10 02 P.M. PST NOV. 10 02 P.M. PST NOV. 10 04 P.M. PST 1 01 A.M. PST 1 05 A.M. PST 1 07 A.H. PST 1 10 A.N. PST 1 02 P.M. PST 1 11 P.M. PST 1 11 P.M. PST 2 08 A.M. PST 2 10 A.M. PST 2 05 P.H. PST 2 11 P.M. PST 3 06 A.M. PST 3 04 P.M. PST 3 08 P.M. PST 3 10 P.M. PST 5 09 A.M. PST 5 09 P.M. PST 5 11 P.M. PST 6 03 P.M. PST 9 03 A.M. PST 9 03 A.M. PST 9 09 A.M. PST 9 10 A.M. PST

1 09 P.M. PST 2 01 P.M. PST 4 03 A.M. PST 4 07 P.M. PST 9 07 A.M. PST 9 11 P.M. PST

NOV. 11 NOV. 11 NOV. 13 NOV. 13 NOV. 13 NOV. 14 NOV. 16 NOV. 16 NOV. 16 NOV. 17 NOV. 18 NOV. 24 NOV. 27 DEC. DEC. DEC. DEC. 10 DEC. 10 DEC. 12 DEC. 13 DEC. 14 DEC. 15 DEC. 16 DEC. 16 DEC. 18 DEC. 19 DEC. 20 DEC. 20 DEC. 20 DEC. 24 DEC. 27 DEC. 30

OCT. 12 OCT. 17 OCT. 21 OCT. 29 NOV. 11 NOV. 20

NOV.

OCT. OCT. OCT. OCT. OCT. OCT. 11 OCT. 14 OCT. 15 OCT. 15 OCT. 19 OCT. 23 OCT. 28 NOV. NOV. NOV. 10 00 30 56.6 20 25 10.2 03 00 00.2 03 07 47.6 03 50 21.9 17 57 44.5 07 29 53.5 12 01 45.5 19 47 05.6 02 53 40.4 16 15 49.2 09 20 17.7 01 25 12.0 02 57 30.0 21 32 37.4 22 58 23.0 09 33 20.2 11 57 37.8 15 11 09.1 01 20 01.0 11 32 59.2 08 05 33.9 01 34 52.3 14 33 46.2 14 41 44.9 20 56 52.9 07 41 49.7 10 25 29.5 15 29 55.4 02 22 07.7 20 24 15.5 02 12 26.3

07 39 18.9 15 44 34.3 21 43 40.5 01 42 28.0 09 35 43.4 17 21 19.0 05 11 22.8 00 38 20.5 11 00 00.2 20 08 35.6 07 56 08.9 09 33 32.3 02 05 50.6 17 23 46.8 13 02 56.6 CALIFORNIA--Continued

35.02 N. 119.17 w. 35.77 N. 117.72 w. 37.62 N. 118.97 w. 37.63 N. 118.97 w. 37.64 N. 118.96 w. 34.07 N. 118.02 w. 11 36.43 N. 121.04 w. 35.05 N. 119.15 w. 37.06 N. 121.45 w. 33.70 N. 119.13 w. 16 37.49 N. 119.54 w. 34.85 N. 116.65 w. 32.03 N. 115.80 w. 37.59 N. 118.89 w. 39.58 N. 123.22 w. 33.68 N. 119.13 w. 16 37.43 N. 118.46 w. 19 38.80 N. 122.56 w. 37.38 N. 122.28 w. 38.67 N. 118.24 w. 33.67 N. 119.15 w. 25 36.10 N. 117.83W. 36.20 N. 117.90 w. 33.77 N. 118.05 w. 38.28 N. 122.63 w. 38.63 N. 118.21 w. 17 38.29 N. 122.62 w. 38.29 N. 122.58 w. 38.29 N. 122.57 w. 34.02 N. 116.77 w. 20 34.25 N. 117.62 \1. 39.51 N. 123.39 w.

CALIFORNIA--OFF THE COAST 40.90 N. 125.70 w. 40.45 N. 125.31 w. 40.45 N. 125.40 w. 40.23 N. 127.11 w. 40.22 N. 124.53 w. 40.52 N. 124.91 w.

COLORADO 39.52 N. 105.30 w.

HAWAII 19.34 N. 155.03 w. 19.34 N. 155.12 w. 19.34 N. 155.12 w. 19.28 N. 155·.52 w. 28 19.31 N. 155.23 w. 10 19.62 N. 156.07 w. 38 19.28 N. 155.36 w. 20.00 N. 155.67 w. 14 18.98 N. 155.06 w. 35 19.33 N. 155.18 w. 19.32 N. 155.15 w. 10 19.38 N. 155.28 w. 33 19.48 N. 155.88 w. 11 19.33 N. 155.22 w. 10 19.34 N. 155.22 w. 10

------------------- inten1ity source ----------------------

5.3 3.2P 3.2P 3.8B FELT 3.7B FELT 3.2B ..!.9P FELT 3.1B 3.1P 2.9B 3.0P 3.8B FELT 3.5P 3.0P 3.0B 2.6B 3.3P FELT 3.5B 3.3B FELT 3.8B 3.7B 3.8P FELT 3.8P 3.5P 2.1P FELT 3.1B 4.4B 3.2B FELT 2.6B FELT 2.8B FELT 3.0P 3 .1P 2.6B

4.0B 3.0B 3.4B 4.3B 4.0B 3.8B

3.1H 3.1H 3.1H 3.7H 3.0H 3.0H 3.1H 3.1H 3.3H 3.0H 3.3H 4.0H 3.1H 3.1H 4.4H IV

v B DEC. 12 07 A.M. PST

... p DEC. P.M. PST IV

... B OCT. P.M. PST IV

v G NOV.

... H OCT. 1 P.M. HST III III

... H OCT. P.M. HST v H OCT. .27 11 P.M. HST III v H NOV. 10 03 A.M. HST p NOV. p NOV. B NOV. 12 07 P.M. PST B NOV. 12 07 P.M. PST B NOV. 12 07 P.M. PST p NOV. B NOV. 15 11 P.M. PST p NOV. B NOV. 16 11 A.M. PST p NOV.

B NOV. 18 08 A.M. PST p NOV. p NOV. B DEC. B DEC. p DEC.

DEC. 10 01 A.M. PST B DEC. 10 03 A.M. PST B DEC. 12 05 P.M. PST p DEC. p DEC. p DEC. p DEC. B DEC. 18 06 A.H. PST B DEC. 19 12 P.M. PST B DEC. 19 11 P.M. PST G DEC. 20 02 A.M. PST G DEC. 20 07 A.M. PST p DEC.

B DEC. 29 06 P.M. PST

B OCT. 11 04 P.M. PST B OCT. 16 07 P.M. PST B OCT. 20 11 P.M. PST B NOV. 11 09 A.M. PST B NOV. 20 03 P.M. PST

H OCT. H OCT. H OCT. H OCT. H OCT. 11 07 A.M. HST H OCT. 13 07 P.M. HST H OCT. 14 02 P.M. HST H OCT. 15 01 A.M. HST H OCT. 19 10 A.M. HST

H NOV. H NOV. 10 04 P.M. PST 11 12 P.M. PST

14 09 A.M. PST 16 04 A.M. PST 16 06 P.M. PST

24 01 A.M. PST 26 05 P.M. PST 1 06 P.M. PST 7 01 P.H. PST 9 02 P.M. PST

14 03 A.M. PST 15 00 A.H. PST 15 05 P.H. PST 16 06 A.M. PST

23 06 P.M. PST

1 08 P.M. MST

2 05 A.M. RST 2 11 A.M. HST 4 03 P.M. HST 6 11 P.M. HST

1 04 P.M. HST 7 07 A.M. HST NOV. NOV. NOV. NOV. NOV. NOV. NOV. NOV. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC. DEC.

DEC. DEC.

NOV. 30 DEC.

OCT.

OCT. OCT. 13 OCT. 13 OCT. 15 NOV. NOV. 11 NOV. 12 NOV. 19 NOV. 19 DEC. DEC. DEC. DEC. 16 DEC. 28

DEC.

OCT. 21 13 31 02.6 06 23 59.4 12 26 40.2 05 10 09.5 08 29 54.8 05 32 58.1 17 42 52.4 19 17 18.4 06 07 09.7 22 26 30.9 19 07 29.1 03 39 27.2 04 23 13.3 13 22 28.8 00 20 21.3 06 21 51.5 15 08 02.6 05 15 15.6 17 11 14.6 02 09 30.4

16 49 06.7 19.34 N. 155.21 w. 19.97 N. 155.35 w. 10 19.96 N. 155.36 w. 12 19.28 N. 155.37 w. 19.37 N. 155.48 w. 11 19.96 N. 155.35 w. 12 19.37 N. 155.08 w. 19.97 N. 155.35 w. 10 155.08 \1. 19.36 N. 19.33 N. 155.13 w. 19.32 N. 155.22 w. 19.82 N. 156.07 w. 41 19.33 N. 155.09 w. 10 19.35 N. 155.07 w. 19.33 N. 155.14 w. 19.33 N. 155.12 w. 19.34 N. 155.17 w. 19.33 N. 155.12 w. 20.10 N. 155.82 w. 28 19.28 N. 155.37 w.

42.63 N. 111.43 w. 42.64 N. 111.46 w.

37.17 N.

37.63 N. 37.29 N.

41.17 N.

37.08 N. 116.01 w. 37.07 N. 116.93 w. 37.05 N. 116.97 w. 37.07 N. 116.95 w. 39.42 N. 119.72 w. 37.08 N. 116.07 w. 37.11 N. 116 .os w. 39.26 N. 116.39 w. 37.07 N. 116.88 w. 38.62 N. 118.19 w. 11 37.15 N. 116.07 w. 38.67 N. 118.22 w. 37.12 N. 116.12 w. 37.21 N. 114.98W.

34.46 N. 108.23 w.

41.15 N.

89.32 w.

82.20 w. 82.92 w.

98.54 w.

72.58 w.

3.4H 3.0H 3.4H 3.0H 3.6H 3.8H 3.4H 3.4H 3.4H 3.3H 3.2H 4.0H 3.7H 3.0H 3.3H 3.4H 3.1H 3.2H 3.0H 3.2H

5.0B 3.4P 3.1P 3.5P 3.3B 4.8B 5.5B 3.5G 3 .1P 4.5B 4.9B 4 .1B 4.4B 3.6G

3.8J H NOV. 10 03 A.M. HST III H NOV. III III H NOV. H NOV. 16 07 P.H. HST

"iv

H NOV.

VI H NOV. 19 07 P.M. HST IV H NOV. III H NOV. 28 09 A.M. HST H NOV. 30 08 P.M. HST III H DEC. Ill H DEC. H DEC. IV III H DEC. 12 06 P.M. HST H DEC. 13 03 A.M. HST H DEC. 13 02 P.M. HST

iii

III H DEC. 16 08 P.M. HST H DEC. 20 05 A.M. HST H DEC. 21 07 P.M. HST II H DEC. 23 07 A.M. HST H DEC.

v u DEC.

u DEC.

K DEC. 27 03 P.M. CST

K NOV. 30 12 P.M. EST v DEC.

G OCT.

E OCT.

p OCT. OCT. 13 11 A.M. PST p OCT. v R NOV.

E NOV. 11 12 P.M. PST E NOV. 12 07 A.M. PST G NOV. 19 10 A.M. PST G NOV. 19 01 P.M. PST v B DEC.

E DEC.

IV B DEC. E DEC. 16 01 P.M. PST IV G DEC. 28 02 P.M. PST

G DEC.

v J OCT. 21 11 A.M. EST 15 08 P.M. HST 16 02 A.M. HST 18 10 P.M. HST

20 07 A.M. HST

27 04 P.M. HST

13 06 A.M. PST 14 08 P.M. PST 5 12 P.M. HST 7 09 A.M. HST 7 05 P.M. HST

9 01 A.M. MST 9 01 A.M. MST

7 03 P.M. EST

9 03 P.M. CST

1 11 A.M. PST

4 03 A.H. PST

1 08 A.M. PST 3 07 A.M. PST 6 11 P.M. PST

4 01 A.M. MST

OCT. 20 NOV. NOV. NOV. 11 NOV. 16 NOV. 22 DEC. DEC. 14 DEC. 20 DEC. 21

OCT. 22 NOV. NOV. 25

NOV.

NOV. 23 DEC.

OCT. 25 NOV. 12 NOV. 26

OCT. OCT. 18 NOV. 15 DEC. 15 DEC. 15 18 35 46.7 13 47 34.1 08 31 24.0 02 49 00.8 13 03 55.3 11 37 56.6 20 05 26.0 16 14 11.7 20 30 06.8 10 57 49.9

16 49 32.2 10 10 40.2 02 36 21.6 14 17 58.1 15 36 10.5 43.10 N. 126.26 w. 10 43.54 N. 127.71 w. 10 43.71 N. 127.66 w. 10 43.82 N. 127.35 w. 10 43.80 N. 127.90 w. 10 43.60 N. 127.34 w. 10 42.50 N. 126.83 w. 10 42.03 N. 127.01 w. 10 43.82 N. 127.68 w. 10 43.66 N. 127.40 w. 10

36.30 N. 36.10 N. 35.64 N.

32.02 N.

40.33 N. 111.64 W.

38.24 N. 36.98 N.

47.76 N. 120.17 w. 47.95 N. 122.42 w. 28 47.66 N. 122.63 w. 25

44.23 N. 110.79 w. 44.78 N. 110.71 w. 44.97 N. 110.99 w. 42.89 N. 110.99 w. 42.92 N. 110.98 w.

TENNESSEE 89.44 w. 89.39 w. 12 84.63 w.

95.26 w.

79.09 w. 10 80.78 w.

4:o

6 October (G) Central Alaska

16 October (G) Southern Alaska

6:2 s:sB

Origin time: Epicenter: Depth: Magnitude: Intensity IV: Fairbanks.

Origin time: Epicenter: 2.5K FELT 3.0G 2.6G

2 .1V 2.1V FELT

2.4G FELT 3.9G 3 .1G

3.0G 2 .1G 3.0G 2.9G 2.9G G OCT. 20 10 A.M. PST G NOV. G NOV. NOV. 10 06 P.M. PST G NOV. 16 05 A.M. PST G NOV. 22 03 A.M. PST G DEC. G DEC. 14 08 A.M. PST G DEC. G DEC.

K OCT. 22 04 A.M. CST IV s NOV. K NOV. 25 06 A.M. EST

IV G NOV.

IV U DEC. 17 03 A.M. MST

IV V NOV. 23 08 A.M. EST V DEC.

w OCT. 07 P.M. PST IV w NOV. 12 10 A.H. PST IV w NOV. 26 04 A.M. PST

III G OCT. IV G OCT. 18 03 A.M. M.ST Ill G NOV. G DEC. 15 07 A.M. MST G DEC. 15 08 A.M. HST

18 35 Not located. None computed. 2.3 ML(A)

07 52 50.4 60.91 N., 147.01 W. 20 12 P.M. PST 21 02 A.M. PST

14 07 P.M. MS'l' 3 05 A.M. PST 8 00 A.M. PST

8 12 P.M. PST

8 11 A.M. CST

6 06 A.M. CST

3 09 P.M. EST

8 09 A.M. :HST ALASKA--Continued

Depth:

Hagnitude:

Felt at Anchorage, Cordova, and Valdez (M).

9 November (G) Fox Islands, Aleutian Islands Origin time: Epicenter: Depth: Magnitude:

Intensity IV: Unalaska (H).

14 November (G) Unimak Island region Origin time: Epicenter: Depth: Magnitude: Intensity III: Cold Bay.

16 November (G) Southern Alaska Origin time: Epicenter: Depth: Magnitude: Intensity II: Homer (H).

17 November (G) Kenai Peninsula Origin time: Epicenter: Depth: Magnitude: Intensity IV: Clam Gulch, Cooper Landing, Girdwood, Homer, Kasilof, Kenai, Ninilchik, Soldotna, Sterling, Tyonek. Intensity III: Anchor Point, Anchorage, Nikishka, Whittier. Intensity II: Palmer (M).

18 November (G) Central Alaska Origin time: Epicenter: Depth: Magnitude: Intensity IV: Nenana (M). Intensity II: Fairbanks (M). Felt:

19 November (G) Southern Alaska Origin time: Epicenter: Depth: Magnitude: Intensity III: Anchorage (M).

23 November (G) Kenai Peninsula Origin time: Epicenter: Depth: Normal 4.2 mb(G), 4.2 ML(M)

16 45 06.0 53.22 N., 165.75 W. Normal 5.5 mb(G), 5.3 MS(G), 5.4 MS(B)

00 43 03.3 54.07 N., 164.54 w.

5.1 mb(G)

23 49 48.0 60.11 N., 153.12 W. 126 km 4.5 mb(G)

11 28 40.8 60.31 N., 151.74 W. 74 km 4.8 mb(G)

06 16 08.5 64.58 N., 149.21 w. 10 km 3.4 ML(M)

Chena Ridge (press report).

01 45 33.7 61.40 N., 149.96 W. 45 km 2.8 ML(M)

07 27 34.6 60.69 N., 151.19 W. 86 km ALASKA--Continued

Magnitude:

Intensity III: Anchorage and Kenai (M).

6 December (G) Southern Alaska Origin time: Epicenter: Depth: Magnitude: Intensity IV: Sheep Mountain Lodge and Big Lake (M).

Southern Alaska 7 December (G)

Origin time:

Epicenter:

Depth:

Magnitude:

Intensity III:

8 December (G) Central Alaska Origin time: Epicenter: Depth: }ffignitude: Intensity III: Fairbanks.

18 December (G) Southern Alaska Origin time: Epicenter: Depth: Magnitude: Intensity III: Alaska Railroad Dispatch, Anchorage (H).

20 December (G) Southern Alaska Origin time: Epicenter: Depth: Magnitude:

Intensity III: Anchorage (M).

30 December (G) Central Alaska Origin time: Epicenter: Depth: Magnitude: Intensity IV: Ester, Fairbanks, Fort wright.

30 December (G) Central Alaska Origin time: Epicenter: Depth: Magnitude:

Felt from Delta Junction to the Ester-Fairbanks area (M). None computed

17 27 41.6 61.97 N., 148.40 W. 63 km 4.6 mb(G)

17 45 40.1 61.90 N., 147.65 W. Normal 2.9 ML(M) Chickaloon and Sheep Mountain

14 06 59.0 64.83 N., 147.49 W. 15 km 3.0 ML(M)

14 20 45.5 61.29 N., 150.20 W. Normal 2.1 ML(M)

10 52 06.4 61.27 N., 150.30 W. 65 km None computed.

13 47 26.7 64.51 N., 147.99 W. 15 km 3.9 mb(G), 4.2 ML(M) Wain-

14 00 33.5 64.56 N., 148.09 W. 24 km 4.9 mb(G), 4.6 HS(G), 5.2 ML(M)

10 October (B) Northern California Origin time: Epicenter: Depth: Magnitude:

Felt at Redding (B).

20 October (P) Southern California Origin time: Epicenter: Depth: Hagnitude: Intensity IV: Palm Desert (press report). Felt: -villey (P).

21 October (P) Southern California Origin time: Epicenter: Depth: Magnitude:

Felt at Hemet (P).

26 October (B) Owens Valley area Origin time: Epicenter: Depth: Magnitude: Intensity lii: Bishop (press report).

28 October (P) Southern California Origin time: Epicenter: Depth: Magnitude: Intensity III: Granada Hills, Van Nuys. Felt:

9 November (P) Imperial Valley Origin time: Epicenter: Depth: Magnitude: Intensity IV

10 November (P) Southern California Origin time: Epicenter: Depth: Magnitude:

Intensity V:

the places listed below were few items thrown from store shelves; few small objects overturned and fell; windows, doors, and dishes rattled. Mettler, Pumpkin Center, Ventura. 12 13 17 .8 40.52 N., 122.12 W. 5 km 3.2 ML(B)

12 40 55.6 33.52 N., 116.45 W. 5 km 3.0 ML(P)

Palm Springs and Coachella

05 37 44.7 33.50 N., 116.77 w. 5 km 3.6 ML(P)

14 58 01.8 37.39 N., 118.53 W. 18 km 3.1 ML(B), 2.9 ML(P)

14 17 08.9 34.33 N., 118.52 W. 5 km 3.1 ML(P)

San Fernando.

15 54 40.5 32.83 N., 115.63 W. 6 km 2.7 ML(P) El Centro (press report).

22 34 35.5 35.02 N., 119.13 W. 3 km 4.7 mb(G), 4.6 ML(P), 4.9 ML(B) The most common effects at

Dl8

10 November (P) Southern California

13 November (B) Owens Valley area

13 November (B) Owens Valley area

14 November (P) Southern California

18 November (B) Central California CALIFORNIA--Continued

Intensity IV: Caliente, Cuyama, Delkern, Fellows, Frazier Park, Leona Valley, Oxnard, Taft, Tehachapi. Intensity III: Arvin, Bakersfield, DiGiorgio, Huntington Beach, Inyokern, Lamont, Lebec, Lost Hills, McKittrick, Northridge, Pasadena, Simi Valley, Upland. Intensity II: Edison, Fillmore. Felt:

Angeles (press report), Northwest Los Angeles County (P), Santa Barbara (press report), Thousand Oaks (P), Wheeler Ridge (press report).

Origin time: Epicenter: Depth: Magnitude:

Felt at Mettler and Wheeler Ridge (press report).

Southern California Origin time: Epicenter: Depth: Magnitude:

Felt at Silverado (press report).

Origin time: Epicenter: Depth: Magnitude:

Felt in the Mammoth Lakes area (B).

Origin time: Epicenter: Depth: Magnitude:

Felt in the Mammoth Lakes area (B).

Origin time: Epicenter: Depth: Magnitude:

Felt at El Monte (P).

Origin time: Epicenter: Depth: Covina (P), Lake Hughes, Los

22 37 05.0 35.02 N., 119.18 W. 9 km 4.2 ML(P)

01 19 Not located. None computed. None computed.

03 00 00.2 37.62 N., 118.97 W. 5 km 3.8 ML(B)

03 07 47.6 37.63 N., 118.97 W. 5 km 3.7 ML(B)

17 57 44.5 34.07 N., 118.02 W. 11 km 1.9 ML(P)

16 15 49.2 37.49 N., 119.54 W. 3 km CALIFORNIA--Continued

Magnitude:

Felt in Yosemite National Park (B).

7 December (B) Northern California Origin time: Epicenter: Depth: Magnitude: Intensity IV: Willits (water splashed onto sides of swimming pools and lakes, small objects moved, buildings trembled strongly, felt by many).

10 December (B) Owens Valley area Origin time: Epicenter: Depth: Magnitude:

Felt at Bishop (P), and in Inyo and Mono Counties (press report).

10 December (B) Central California Origin time: Epicenter: Depth: Magnitude:

Felt in the Cobb Mountain area (press report).

Central California 12 December (B)

Origin time:

Epicenter:

Depth:

Felt in San Mateo and Santa Cruz Counties.

Intensity V:

overturned and fell, buildings trembled strongly, felt by many and awakened several). Intensity IV: Belmont, El Granada, Half Moon Bay, La Honda, Menlo Park, Palo Alto, Pescadero, Redwood City, San Mateo, South San Francisco (press report). Felt:

15 December (P) Owens Valley area Origin time: Epicenter: Depth: Magnitude: Intensity IV: Darwin, Kernville.

16 December (P) Southern California Origin time: Epicenter: 3.8 HL(B)

21 32 37.4 39.58 N., 123.22 W. 5 km 2.6 ML(B)

09 33 20.2 37.43 N., 118.46 W. 19 km 3.5 ML(B), 3.0 ML(P)

11 57 37.8 38.80 N., 122.56 W. 6 km 3.3 ML(B)

15 11 09.1 37.38 N., 122.28 W. 9 km 3.8 ML(B)

San Carlos (few small objects

San Francisco (press report).

08 05 33.9 36.10 N., 117.83 W. 4 km 3.8 ML(P), 4.0 ML(B)

14 33 46.2 33.77 N., 118.05 W.

Depth:

Magnitude:

Felt at Los Alamitos and Long Beach (P).

18 December (B) Central California Origin time: Epicenter: Depth: Magnitude: Intensity IV: Intensity III: Felt:

20 December (B)

Origin time:

Epicenter:

Depth:

Magnitude:

Felt at Petaluma and Santa Rosa (B).

20 December (G) Northern California Origin time: Epicenter: Depth: Magnitude:

Felt in the Santa Rosa area (B).

20 December (G)

Origin time:

Epicenter:

Depth:

Magnitude:

Felt in the Santa Rosa area (B).

December (B) Northern California Origin time: Epicenter: Depth: Magnitude: Intensity IV: Willits.

23 October (P) Southern California Origin time: Epicenter: Depth: Magnitude:

This earthquake was felt over approximately 6000 sq km of the land area of Los Angeles, Orange, and Ventura Counties (fig. 7).

CALIFORNIA--OFF THE COAST 6 km 2.1 ML(P)

14 41 44.9 38.28 N., 122.63 W. 5 km 3.1 ML(B) Glen Ellen, Petaluma. Eldridge, Sonoma. Santa Rosa (B).

07 41 49.7 38.29 N., 122.62 W. 5 km 3.2 ML(B)

10 25 29.5 38.29 N., 122.58 w. 5 km 2.6 ML(B)

15 29 55.4 38.29 N., 122.57 W. 5 km 2.8 ML(B)

02 12 26.3 39.51 N., 123.39 w. 1 km 2.6 ML(B)

17 28 16.9 33.63 N., 119.02 w. 12 km 4.7 mb(G), 4.6 ML(P), 4.3 ML(B) FIGURE 7.--Intensity map for the southern California, earthquake of 23 October 1981, 17 28 16.9 UTC. Roman numerals represent Modified isoseismals; Arabic numerals are used to represent these intensities at specific sites.

Intensity V:

the places listed below were few small objects overturned and fell, water splashed onto sides of lakes and swimming pools, and felt by many. Artesia (hairline cracks in plaster and drywall), Long Beach, Nission Hills, San Pedro. Intensity IV: Avalon, Bellflower, Calabasas, Canoga Park, Castaic, Cole, Culver City, Cypress, Glendale, Huntington Park, Laguna Niguel, Lakewood, Lawndale, Lomita, Los Angeles, Manhattan Beach, Marina del Rey, ~~ywood, North Hollywood, Northridge, Norwalk, Paramount, Reseda, San Fernando, Santa Monica, Somis, Southgate, Torrance, Universal City, Van Nuys, Venice, Whittier, Wilmington. Intensity III: Arleta, Bell, Beverly Hills, Buena Park, Calabasas Park, Camarillo, Compton, Downey, El Camino College, East Irvine, Fillmore, Florence, Fullerton, Harbor City, Huntington Beach, La Canada, Laguna Niguel, Los Alamitos, Malibu, Montrose, Oxnard, Pacific Palisades, Palos Verdes Peninsula, Pasadena, Point Mugu, Redondo Beach, San Clemente, Saugus, Sepulveda, South Laguna, South Whittier, Thousand Oaks, Topanga, Ventura, Westminster. !CALIFORNIA

23 October (P) Southern California

The most common effects at CALIFORNIA--OFF THE COAST--Continued

Intensity II: Arcadia, Granada Hills, Santa Barbara (press report), Sun Valley, Sunland. Felt: ~ra Lorna (press report), San Diego (P).

Origin time:

Epicenter:

Depth:

Magnitude:

This event occurred in the same region as the one at 17 28 16.9, listed above, with about the same magnitude and felt over a similar area. Most reports tend to describe the effects as a repeat of the earlier shaking which had a maximum intensity of v.

Intensity IV: San Juan Capistrano.

Intensity III: Costa Mesa, Glendale,

Felt:

4 November (P) Southern California Origin time: Epicenter: Depth: Magnitude:

Felt at Los Angeles (P).

11 November (B)

Origin time:

Epicenter:

Depth:

Magnitude:

Intensity IV: Whitehorn.

Intensity III: Alderpoint, Fields Landing,

11 December Origin time: Epicenter: Depth: Magnitude:

Felt in the beach area of Santa Monica

14 December (P) Southern California Origin time: Laguna Niguel, Ventura.

Mira Lorna (press report), Oxnard (press report), Pasadena (P), San Diego (press report), Santa Barbara (press report), Santa Monica (press report), Studio City (P), Valencia (press report).

Honeydew.

(press report).

19 15 52.5 33.63 N., 119.05 W. 6 km 4.6 mb(G), 4.6 ML(P), 4.3 ML(B)

Burbank (P) La Brea (P),

11 54 56.1 33.90 N., 118.63 W. 6 km 2.7 ML(P)

Northern California 17 46 07.5 40.22 N., 124.53 W.

3.7 mb(G), 4.0 ML(B)

Southern California 18 42 Not located. None computed. None computed.

11 32 59.2 CALIFORNIA--OFF THE COAST--Continued

Epicenter:

Depth:

Magnitude:

Felt in the beach area of Santa Monica (press report).

2 November (G) Central Colorado Origin time: Epicenter: Depth: Magnitude: Intensity V:

9 December Central Colorado Origin time: Epicenter: Depth: Magnitude:

This earthquake is an aftershock of the event on November 2. It was felt at Evergreen.

33.67 N., 119.15 W.

25 km 3.8 ML(P)

03 03 00.2 39.52 N., 105.30 W. 1 km 2.8 ML(G), 3.1 Mn(T) Morrison--South Turkey Creek

02 45 36.2 Not located. ~one computed. None computed. CONNECTICUT

21 October (J) Long Island Sound Origin time:

See New York listing.

2 October (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III: Hilo.

5 October (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III: Pahala.

14 October (H) Island of Hawaii Origin time: Epicenter: Depth:

Intensity II: Pahala.

15 October (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III: Waimea.

28 October (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity V: Intensity IV: Glenwood, Hilo. Intensity III: Kona, Pahala.

7 November (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity III: Volcano.

10 November (H) Island of Hawaii Origin time: Epicenter: Depth: Magnitude: Intensity V:

thrown from store shelves--press report). 16 49 06.7

15 44 34.3 19.34 N., 155.12 W. 9 km 3.1 ML(H)

01 42 28.0 19.28 N., 155.52 W. 28 km 3.7 ML(H)

05 11 22.8 19.28 N., 155.36 W. 9 km 3.1 ML(H)

00 38 20.5 20.00 N., 155.67 W. 14 km 3.1 ML(H)

09 33 32.3 19.38 N., 155.28 W. 33 km 4.0 ML(H) Volcano.

17 23 46.8 19.33 N., 155.22 W. 10 km 3.1 ML(H)

13 02 56.6 19.34 N., 155.22 W. 10 km 4.4 UL(H) Hilo, Opihikao (few items

w.

w.

w.

D22

Intensity V:

store shelves, small objects fell, and windows, doors and dishes rattled), Soda Springs (hairline cracks in plaster and drywall, small objects fell and windows, doors and dishes rattled). Intensity IV: Paris. Intensity III: Lava Hot Springs. Intensity II: Pocatello.

7 December (V) Eastern Kentucky Origin time: Epicenter: Depth: Hagnitude:

An explosion in a coal mine about 3 miles south of Topmost. Five miners were killed and three were missing.

October (E) Southern Nevada Origin time: Epicenter: Depth:

Nevada Test Site explosion "PALIZA" at 37°04'53.82" N., 116°00'31.51" W., surface elevation 1287 m, depth of burial 472 m.

4 November (R) Western Nevada Origin time: Epicenter: Depth: Magnitude: Intensity V:

turned and fell; hanging pictures swung;

windows, doors, and dishes rattled).

Intensity III: Silver City.

Intensity II: Carson City.

11 November (E) Southern Nevada Origin time: Epicenter: Depth: Magnitude:

Gonda (few items thrown from

20 01 10.5 37.29 N., 82.92 w. 0 km None Computed.

19 00 00.103 37.08 N., 116.01 W. 0 km 4.9 mb(G), 5.0 HL(B), 5.2 NL(P)

11 47 18.9 39.42 N., 119.72 W. 2 km 3.3 ML(B) Reno (few small objects over-

20 00 00.036 37.08 N., 116.07 W. 0 km 4.8 mb(G), 4.8 ML(B), 5.0 ML(P) NEVADA--Continued

Nevada Test Site explosion "TILCI" at 37°04'34.76" N., 116°04'06.57" W., surface elevation 1259 m, depth of burial 445 m.

12 November (E) Southern Nevada Origin time: Epicenter: Depth: Magnitude:

Nevada Test Site explosion "ROUSANNE" at 37°06'29.35" N., 116°02'56.31" w., surface elevation 1270 m, depth of burial 518 m.

December (B) Western Nevada Origin time: Epicenter: Depth: Magnitude: Intensity V:

store shelves, few small objects overturned and fell, buildings trembled strongly, felt by all and awakened many). Intensity IV: Mina. Intensity II: Gabbs.

3 December (E) Southern Nevada Origin time: Epicenter: Depth: Magnitude:

Nevada Test Site explosion "AKAVI" at 37°08'54.35" N., 116°04'15.01" W., surface elevation 1320 m, depth of burial 494 m.

7 December (B) Western Nevada Origin time: Epicenter: Depth: Magnitude: Intensity IV: Luning, Mina. Intensity III: Hawthorne.

16 December (E) Southern Nevada Origin time: Epicenter: Depth:

Nevada Test Site explosion "CABOC" at 37°06'52.29" N., 116°07'22.36" W., surface elevation 1375 m, depth of burial 335 m. 15 00 00.100 37.11 N., 116.05 W. 0 km 5.3 mb(G), 4.4 MS(G), 5.5 ML(B), 5.3 ML(P)

16 18 50.0 38.62 N., 118.19 W. 11 km 4.5 ML(B) Luning (few items thrown from

15 00 00.098 37.15 N., 116.07 W. 0 km 4.6 mb(G), 4.9 ML(B)

07 47 51.6 38.67 N., 118.22 W. 6 km 4.1 :HL(B)

21 05 00.093 37.12 N., 116.12 W. 0 km 4.4 mb(G), 4.4 ML(B) FIGURE B.--Intensity survey of the October 21, 1981 earthquake in Long Island Sound, New York. Larger symbols represent the modal values of reported intensities for a given locality, and smaller symbols represent either single reports or reports from localities for which there was no well defined mode (provided by Schlesinger-Miller, Lamont-Doherty Geological Observatory).

28 December (G) Southern Nevada Origin time: Epicenter: Depth: Magnitude: Intensity IV:

Arizona--Temple Bar.

Nevada--Blue Diamond, Henderson, Las Vegas, North Las Vegas, Pioche. Utah--Toquerville. Felt: ~vada--Alamo and Boulder City (press report).

4 December (G) Western New Mexico Origin time: Epicenter: Depth: Magnitude:

Felt south of Grants (telephone report).

io

21 October (J) Long Island Sound 22 45 42.1 37.21 N., 114.98 W. 5 km 3.6 ML(G)

Intensity V:

08 51 24.2 34.46 N., 108.23 W. 5 km 2.8 ML(G) Origin time: Epicenter: Depth: Magnitude:

Felt in southern Connecticut, Long Island and vicinity, New York, and western Rhode Island. This is the first event to be located instrumentally within the Sound (Pulli and Godkin, 1981). The extent of the felt area mapped by Schlesinger-Miller, Lamont-Doherty Geological Observatory is shown on the intensity map in figure 8; however, it does not reflect all the intensity values listed below.

The most common effects at the places listed below were hairline cracks in plaster and drywall, few items thrown from store shelves, few small objects overturned and fell, few glassware and dishes broke, few windows cracked, felt by many. Connecticut--Centerbrook, Chester, East Lymes (foundation cracked), Essex, Gales

-v-•

16 49 06.7 41.15 N., 72.58 W.

3.8 Mn(J), 3.4ML(J) NEW YORK--Continued

Ferry, Middle Haddam, Moodus, Mystic, Old Saybrook, Seymour, South Lyme, Stratford. New York--Mastic Beach (a chandelier fell and dishes fell from shelves--press report), south shore of Suffolk County (dishes fell from shelves--press report). Intensity IV:

Connecticut--Clinton, Deep River, Derby, East Hampton, Groton, Guilford, Haddam, Hadlyme, Madison, Monroe, Saybrook (press report), Westbrook (press report). New York--Great Kills (press report), Hauppauge (press report), Todt Hill (press report). Intensity III:

Connecticut--Colchester, East Haddam, Haddam, Higganum, Ivoryton, Portland, New Haven (press report), New London, Niantic, Nurtl<ford, Quaker Hill, Stevenson. New York--Commack, East Chester, Greenburg, Orient Point, Port Chester, Riverhead, Rye, Sea Cliff, Yorktown (all from press reports). Intensity II:

Connecticut--Old Mystic.

New York--Shelter Island, Waterbury, and West Hempstead (press reports). Felt: --connecticut--Danbury (press report), Middletown (press report), Norwich (press report), Uncasville, Waterbury (press report). Rhode Island--Western tip.

21 October (J) Long Island Sound Origin time:

See New York listing.

22 October (K) Northwestern Tennessee Origin time: Epicenter: Depth: Magnitude:

Felt at Ridgely (K). 16 49 06.7

10 33 29.3 36.30 N., 89.44 W. 3 km 2.5 MD(K) TENNESSEE--Continued

8 November (S) Northwestern Tennessee Origin time: Epicenter: Depth: Magnitude:

Intensity IV: Dyersburg, Newbern.

Epicenter:

Depth:

Magnitude:

Intensity IV: Jacksonville (press repor ), Mount Enterprise (press report), NewS mmerfield.

17 December (U) Central Utah Origin time: Epicenter: Depth: Magnitude: Intensity IV: Edgemont and Orem (press report). Felt: --rPress report).

28 December (G) Southern Nevada Origin time:

See Nevada listing.

Origin time:

Epicenter:

Depth:

Magnitude:

Intensity IV: Staunton.

Felt:

--rtelephone report). 17 11 19.0 · 36.10 N., 89.39 W. 12 km 3.0 Mn(G), 2.5 Mn(T), 2.9 MD(K)

32.02 N., 95.26 W. 5 km 3.2 Mn(T), 2.9 MD(K)

10 47 43.5 40.33 N., 111.64 W. 2 km 2.2 ML(U)

Provo and Utah Counties

13 14 51.0 38.24 N., 79.09 W. 10 km 2.1 MD(V)

Churchville, Frank's Mill VIRGINIA--Continued

4 December (V) Southwestern Virginia Origin time: Epicenter: Depth: Magnitude: Felt:

25 October (W) Central Washington Origin time: Epicenter: Depth: Magnitude:

Felt in the Chelan area (press report).

12 November (W) Northwestern Washington Origin time: Epicenter: Depth: Magnitude: Intensity IV: Everett (press report), Freeland, Gold Bar, Langley, Lynnwood (Seattle--press report), Marysville, Monroe, Mulkilteo, Nordland, Port Ludlow, Poulsbo, Seattle, Silvana, Woodinville. Intensity III: Clinton, Conway, Granite Falls, Hansville, Keyport, Kingston, Lake Stevens, Northgate, Oak Harbor, Port Gamble, Snohomish. Intensity II: Quilcene, Rollingbay. Felt: --L;iewood.

26 November (W) Western Washington Origin time: Epicenter: Depth: Magnitude: Intensity IV: Fox Island, Indianola, Port Orchard, Seabeck. Intensity III: Bremerton, Milton, Tahuya. Felt:

8 October (G) Yellowstone National Park Origin time: Epicenter: Depth: Magnitude: Intensity III: Old Failthful. 02 35 56.2 36.98 N., 80.78 w. 8 km 2.1 Mn(V) Pulaski (V).

03 21 03.6 47.76 N., 120.17 W. 0 km 2.4 ML(G), 2.7 MD(W)

18 10 24.9 47.95 N., 122.42 W. 28 km 3.9 ML(G)

12 30 00.7 47.66 N., 122.63 W. 25 km 3.1 ML(G)

East Union, Shelton.

16 49 32.2 44.23 N., 110.79 W. 1 km 3.0 ML(G)

18 October (G) Yellowstone National Park Origin time: Epicenter: Depth: Magnitude: Intensity IV: Norris Geyser Basin.

15 November (G) Yellowstone National Park Origin time: Epicenter: Depth: Magnitude: Intensity III: Madison Junction. Intensity II: Old Faithful.

ACKNOWLEDGMENTS

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

CALIFORNIA:

MASSACHUSETTS: Staff of Weston Observatory, Bos-

MISSOURI:

MONTANA:

NEVADA:

NEW YORK:

OKLAHOMA:

Staff of National Oceanic and Atmospheric Administration, Alaska Tsunami Warning Center, Palmer. Clarence R. Allen, Seismological Laboratory, California Institute of Technology, Pasadena. Bruce A. Bolt, Seismograph Station, University of California, Berkeley. Robert Y. Koyanagi, U.S. Geological Survey, Hawaiian Volcano Observatory, Hawaii National Park.

ton College, Weston. Robert Herrmann and Otto Nuttli, Department of Geology and Geophysics, St. Louis University, St. Louis. Anthony Qamar, University of Montana, Missoula. Alan S. Ryall, University of Nevada, Reno. Lynn R. Sykes and Alan L. Fafka, Lamont-Doherty Geological Observatory, Columbia University, Palisades. James E. Lawson, Jr., Oklahoma Geophysical Observatory, Oklahoma Geological Survey, Leonard. 10 10 40.2 44.78 N., 110.71 W. 1 km 2.1 MD(G)

02 36 21.6 44.97 N., 110.99 W. None computed. 3.0 MD(G). TENNESSEE:

UTAH:

VIRGINIA:

WASHINGTON:

REFERENCES CITED

Bath, Markus, 1966, Earthquake energy and magnitude, in Physics and chemistry of the Earth, Volume 7: Oxford and New York, Pergamon Press, p. 115-165.

A. Johnson, Tennessee Earthquake Information Center, Memphis State University, Nemphis.

Department of Geology and Geophysics, University of Utah, Salt Lake City.

G. A. Bollinger, Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg.

Robert S. Crosson, Geophysics Program, University of Washington, Seattle.

Gutenberg, B. and Richter, C. F., 1956, agnitude and energy of earthquakes: Ann,li di Geofisica, v. 9, no. 1, p. 1-15.

Nuttli, 0. W., 1973, Seismic wave atten ation and magnitude relations for eastern North America: Journal of Geophysical Research, v. 78, no. 5, p. 876-885.

Pulli, J. J. and Godkin, C. B., 1981, The Long Island Sound, New York, earthquak of October 21, 1981: Eastern Section, Se"smological Society of America, Earth uake Notes, v. 52, no. 4, p. 23-27.

Richter, c. F., 1958, Elementary seismo ogy: San Francisco, W. H. Freeman, P• 768.

Wood, H. 0. and Neumann, F., 1931, Modified Mercalli Intensity Scale of 1931: Seismo ogical Society of America Bulletin, v. 21 no. 4, P• 277-283.

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