DISCLAIMER -- THIS IS NOT AN EARTHQUAKE PREDICTION OR WARNING! The commentary provided with these map(s) is for INFORMATIONAL USE ONLY, and SHOULD NOT be construed as an earthquake prediction, warning, or advisory. Responsibility for such warnings rests with the Office of Emergency Services of the State of California. PLEASE REMEMBER -- THESE ARE PRELIMINARY DATA Releasing these summaries on a timely basis requires that the data, analysis, and interpretations presented are PRELIMINARY. Of necessity they can only reflect the views of the seismologists who prepared them, and DO NOT carry the endorsement of the U.S.G.S. Thus while every effort is made to ensure that the information is accurate, nothing contained in this report is to be construed as and earthquake prediction, warning, advisory, or official policy statement of any kind, of the U.S. Geological Survey, or the U.S. Government. FOR QUESTIONS CONCERNING THIS REPORT Send e-mail to michael@andreas.wr.usgs.gov DO NOT SEND EMAIL TO weekly@garlock.wr.usgs.gov It will not be read. Seismicity Report for Northern California, the Nation, and the World for the week of March 27 - April 2, 1997 Stephen R. Walter U.S. Geological Survey 345 Middlefield Rd. MS-977, Menlo Park, CA 94025 San Francisco Bay Area During the seven day period ending at midnight on Wednesday, April 2, 1997 the U.S. Geological Survey office in Menlo Park recorded 34 earthquakes of magnitude one (Mm) and greater within the San Francisco Bay area shown in Figure 1. Sixteen were as large as M2, including eleven M3 shocks in the Suisun Bay area southeast of Fairfield. This total compares to 18 earthquakes during the prior seven day period (March 20 - 26), nine of which were as large as M2. The Fairfield activity began last Wednesday and was briefly mentioned in last week's summary. The first M3 quake occurred early last Thursday morning and was followed by eight more M3 events over the next 12 hours (#1/1). The M3 events were felt in the Fairfield-Pittsburg-Concord areas, though none produced any significant damage. Activity declined later Thursday afternoon - four events as large as M2 occurred through Saturday - but resumed Monday evening/Tuesday morning with a pair of M3's. While this was one of the more active sequences seen in this area in the past 25 years, the size of the earthquakes was not that unusual. Nearly 20 M3 earthquakes have been recorded in this area since 1970 including two that were as large as M4.2. Like previous earthquakes in this area, last week's earthquakes were all located at depths of 20 to 23 km. This is about ten km deeper than earthquakes occur along most other faults in the Bay Area. A M2.5 event west of Cupertino was reported to have been felt by some residents in the immediate epicentral area (#2/1). Only slightly smaller but apparently unfelt were a pair of M2's on the central Calaveras fault six miles east of Gilroy (#3/1). Finally, a M2.4 event occurred on the northern extension of the Hayward fault beneath San Pablo Bay, about five miles northwest of Pinole (#4/1). Northern & Central California Aside from the Fairfield activity, the region was relatively quiet during the week with only two earthquakes as large as M3. The first of these was a M3.1 along the Nevada border about eight miles east of Markleeville (#4/2). This is much the same location as a M3.2 on March 24. The second M3 occurred in the Long Valley caldera (see below). The northern Coast Range saw a trio of M2 earthquakes on the northern Maacama fault. Two occurred four miles west of Laytonville on Monday afternoon (#6/2). The third followed on Wednesday morning about five miles east of Willits (#7/2). Earlier in the week a M2.0 occurred near the Bartlett Springs fault four miles southeast of Lake Pillsbury (#1/2). The Geysers geothermal area was a bit more quiet than usual with just four M2 earthquakes, the largest a M2.4 late Wednesday evening. The Cape Mendocino area experienced just one earthquake as large as M2, a 25-km-deep event 28 miles east of Petrolia (#5/2). The only notable activity in central California occurred along the central creeping segment of the San Andreas where four M2 earthquakes were recorded, the two largest both having magnitudes of M2.5 (#2/2). Long Valley Caldera As has been the case so far this year, what activity there was in the area occurred south of the caldera. This week, there was a small cluster of earthquakes just south of the caldera about 2 miles northwest of Convict Lake (#1/3). The activity began with a M2.7 Tuesday morning, continued with a M3.3 and a M2.0 later that evening, and ended (so far anyway) with a M2.3 on Wednesday evening. Tuesday's M3.3 event was likely felt by residents of Mammoth Lakes, just five miles to the northwest. USA Seismicity (March 26 - April 2) The National Earthquake Information Center (NEIS) reported a M2.6 occurred Sunday night in north-central Oregon east of the town of Condon (#1/4). This is the same location where a pair of M2's occurred on March 21. Other notable earthquakes in the contiguous U.S. included a M3.5 near the north end of San Clemente Island (#2/4) and a pair of M3's in central Arizona (#3/4). The largest of these was felt at Flagstaff, Grand Canyon Village, and Valle. The other was felt only at Valle. As is often the case, the largest domestic earthquakes occurred in Alaska. In this case a swarm of over a dozen M4 and M5 events rocked the Rat Islands in the central Aleutian archipelago (#4/5). Somewhat farther to the east a M5.5 occurred in the Andreanof Islands the was felt on the island of Adak. Finally, a M4.8 occurred on the Alaska Peninsula near the southern end of Cook Inlet. The Planet Earth (March 26 - April 2) Two damaging earthquakes occurred on the planet last Wednesday. First was a M5.0 in southern Lebanon that slightly damaged 50 buildings in the Beirut area and the was felt throughout the country, in northern & central Israel, and in Syria (#1/5). It was followed nine hours later by a M4.7 aftershock that was felt over much of the same region. A M5.6 in Kyushu, Japan injured at least 22 people, damages many homes, and produced landslides in the Kagoshima Prefecture (#2/5). Moderate earthquakes that apparently produced no significant damage included M5.0 and M5.6 events south of Panama (#3/5), a M6.0 along the Chile-Bolivia border that was strongly felt at Tacna, Peru and Iquique, Chile (#5/5), and a M5.7 off the northeast coast of Venezuela that was felt strongly on the islands of Tobago and Trinidad and as far north as St. Vincent (#6/5). Table 1. Northern & Central California Seismicity (M>1.0) --ORIGIN TIME (UT)-- -LAT N-- --LON W-- DEPTH N N RMS ERH ERZ DUR YR MON DA HRMN SEC DEG MIN DEG MIN KM RD S SEC KM KM REMKS MAG 97 MAR 27 911 18.56 38 9.26 121 56.04 23.31 33 .17 .5 .4 JQN 2.0 97 MAR 27 1010 45.24 38 8.99 121 56.27 20.68 37 .10 .3 .2 JQN 3.2 97 MAR 27 1017 5.57 38 9.54 121 56.03 23.07 38 1 .16 .3 .4 JQN 2.0 97 MAR 27 1026 35.32 38 8.91 121 56.06 21.57 50 1 .11 .2 .2 JQN 2.8 97 MAR 27 1111 24.55 38 8.94 121 56.45 22.18 54 1 .16 .3 .2 JQN 2.8 97 MAR 27 1130 7.00 38 8.80 121 56.71 21.38 67 2 .18 .3 .2 JQN 3.4 97 MAR 27 1143 14.44 38 49.37 122 48.20 3.81 7 .02 .4 .9 GEY 1.2 97 MAR 27 1315 33.17 38 10.26 122 5.27 10.70 19 .39 .8 2.6 GVL 1.7 97 MAR 27 1338 8.83 38 8.88 121 56.04 21.26 59 2 .14 .2 .2 JQN 3.2 97 MAR 27 1401 24.22 38 8.83 121 56.15 21.37 55 .13 .3 .2 JQN 3.4 97 MAR 27 1533 7.23 38 56.50 123 8.68 5.07 8 1 .03 1.5 3.0 MAA 1.4 97 MAR 27 1539 49.01 38 8.79 121 56.82 21.19 70 1 .23 .4 .3 GRN 3.7 97 MAR 27 1635 19.24 38 10.06 121 55.30 20.04 7 .13 1.1 .9 JQN 1.5 97 MAR 27 1707 37.75 38 9.23 121 56.17 22.89 45 1 .17 .3 .2 JQN 2.4 97 MAR 27 1716 42.85 38 9.27 121 56.86 22.65 60 1 .18 .4 .2 JQN 3.3 97 MAR 27 1801 43.17 38 9.12 121 56.78 21.82 60 .17 .3 .2 JQN 3.3 97 MAR 27 1821 23.45 38 49.59 122 47.68 3.86 12 .03 .2 .7 GEY 1.4 97 MAR 27 1951 35.35 35 59.98 120 32.95 3.83 8 .00 .6 1.6 MID 1.3 97 MAR 27 2216 18.79 38 9.35 121 55.92 21.30 29 .12 .4 .3 JQN 2.5 97 MAR 27 2247 53.00 38 8.91 121 56.35 22.11 63 .16 .3 .2 JQN 3.5 97 MAR 27 2253 7.61 38 8.93 121 56.47 21.71 59 1 .14 .3 .2 JQN 3.4 97 MAR 28 116 26.18 38 49.84 122 48.09 2.99 7 .02 .3 .8 GEY 1.3 97 MAR 28 139 20.01 38 49.58 122 48.08 3.12 8 .02 .3 .7 GEY 1.2 97 MAR 28 144 42.08 38 49.42 122 48.16 3.66 8 .02 .3 .8 GEY 1.2 97 MAR 28 224 42.91 37 26.95 118 50.25 11.90 10 .05 1.7 2.5 MOR 1.5 97 MAR 28 335 58.82 38 11.05 121 58.32 5.01 7 .33 1.421.7 JQN - 1.6 97 MAR 28 426 31.51 37 18.31 122 5.94 5.48 82 1 .16 .1 .3 BLM 2.5 97 MAR 28 501 11.54 38 49.63 122 47.64 3.48 8 .04 .3 .8 GEY 1.4 97 MAR 28 501 22.62 39 23.47 122 53.43 10.03 21 .03 .2 .7 BAR 2.0 97 MAR 28 519 24.74 38 46.40 122 53.44 4.68 16 .07 .3 .8 GEY 1.6 97 MAR 28 639 32.49 36 51.50 121 24.13 7.68 18 .04 .3 .9 HOL 1.0 97 MAR 28 749 41.19 38 47.43 122 46.44 2.95 19 .05 .2 .5 GEY 1.8 97 MAR 28 800 9.82 37 35.58 118 51.51 7.65 10 .04 .6 .5 MOR 1.5 97 MAR 28 904 26.52 37 6.18 121 31.48 3.06 13 .03 .2 .4 CYN 1.1 97 MAR 28 1302 41.96 36 34.37 121 9.88 2.97 52 .07 .1 .3 PIN 2.5 97 MAR 28 1303 47.55 38 9.82 121 55.76 24.07 15 .15 .5 .7 JQN 2.0 97 MAR 28 1648 14.39 37 32.76 118 49.54 12.28 7 .02 2.3 4.0 MOR 1.0 97 MAR 28 1743 49.01 38 48.10 122 44.63 1.66 7 .02 .3 1.0 GEY 1.3 97 MAR 28 2049 22.26 38 0.91 119 9.26 15.82 31 2 .19 .6 2.4 MOL 2.4 97 MAR 28 2246 16.70 38 47.72 122 48.51 4.88 27 .05 .2 .3 GEY 2.1 97 MAR 28 2314 48.29 36 23.56 120 56.07 5.44 7 .04 1.0 3.6 BIT 1.1 97 MAR 29 223 47.95 38 47.10 122 47.51 0.08 9 1 .12 .3 1.1 GEY # 1.4 97 MAR 29 431 9.73 36 59.43 121 28.11 5.70 69 1 .10 .1 .3 CYS 2.4 97 MAR 29 549 47.61 36 59.25 121 28.05 5.58 68 .08 .1 .3 CYS 2.1 97 MAR 29 653 9.11 37 38.76 118 58.69 7.12 9 .02 .7 .9 SMO 1.1 --ORIGIN TIME (UT)-- -LAT N-- --LON W-- DEPTH N N RMS ERH ERZ DUR YR MON DA HRMN SEC DEG MIN DEG MIN KM RD S SEC KM KM REMKS MAG 97 MAR 29 820 46.66 38 9.10 121 55.89 21.85 39 .22 .4 .3 JQN 2.3 97 MAR 29 858 14.39 37 31.96 118 51.14 8.60 21 .06 .3 .7 MOR 1.7 97 MAR 29 931 57.20 37 32.43 118 50.85 8.75 16 1 .05 .3 .6 MOR 1.5 97 MAR 29 946 1.96 38 44.67 119 39.31 7.52 56 2 .10 .3 .7 WAK 3.1 97 MAR 29 1057 35.68 38 48.40 122 46.19 1.94 8 .03 .3 .6 GEY 1.2 97 MAR 29 1156 28.68 37 10.50 122 2.47 6.07 17 2 .07 .2 .3 BLM 1.1 97 MAR 29 1305 23.12 38 10.40 121 57.98 6.86 9 1 .14 .411.8 JQN - 1.7 97 MAR 29 1853 15.32 38 48.12 122 43.96 2.13 10 .03 .2 .6 GEY 1.6 97 MAR 29 1917 56.77 37 38.19 118 51.96 6.64 11 1 .11 .5 .9 SMO 1.2 97 MAR 29 2115 29.65 38 48.31 122 44.78 0.54 8 .04 .3 .8 GEY 1.3 97 MAR 30 18 38.76 38 49.45 122 47.82 3.83 11 .04 .3 .7 GEY 1.4 97 MAR 30 149 33.26 36 51.35 121 35.08 6.64 26 .10 .3 .4 SJB 1.3 97 MAR 30 211 53.36 39 14.58 123 11.75 8.24 12 1 .03 .5 .6 MAA 1.3 97 MAR 30 212 36.36 36 28.03 121 2.36 5.67 50 1 .08 .2 .5 BIT 2.5 97 MAR 30 238 27.15 38 10.58 121 58.43 6.70 8 .09 .410.1 GRN - 1.5 97 MAR 30 308 48.60 39 30.37 123 8.17 0.42 19 2 .18 .4 4.1 BAR # 1.7 97 MAR 30 507 17.25 38 49.17 122 48.56 3.92 14 .03 .2 .5 GEY 1.4 97 MAR 30 515 55.22 35 58.23 120 2.81 9.12 9 .03 1.2 1.4 COA 1.6 97 MAR 30 633 9.70 37 23.95 118 35.13 8.05 9 .34 2.1 4.1 RVL 1.3 97 MAR 30 634 1.35 38 1.43 122 22.86 7.21 70 1 .20 .2 .4 ROG 2.4 97 MAR 30 730 42.29 38 48.72 122 48.75 3.51 10 .03 .3 .5 GEY 1.4 97 MAR 30 740 39.95 38 10.04 121 55.13 24.44 33 .18 .4 .4 JQN 2.0 97 MAR 30 1511 29.62 38 13.69 118 23.36 5.15 23 .06 1.3 8.2 MOL - 2.0 97 MAR 30 1511 48.91 37 8.92 121 32.46 8.31 39 .05 .2 .4 CYN 1.3 97 MAR 30 1632 53.93 38 48.86 122 48.70 3.35 21 .04 .2 .4 GEY 1.8 97 MAR 30 1645 31.52 38 51.08 122 48.87 1.97 16 .05 .2 .8 GEY 1.7 97 MAR 30 1742 14.75 37 38.35 118 56.07 5.60 15 1 .03 .3 .4 SMO 1.2 97 MAR 30 1812 55.47 39 34.33 123 29.29 0.28 9 .08 .6 2.0 MAA 1.6 97 MAR 30 1838 17.95 38 47.98 122 48.73 4.36 8 .03 .4 .8 GEY 1.2 97 MAR 30 2039 4.43 38 48.10 122 48.62 4.19 7 .02 .4 2.0 GEY 1.1 97 MAR 30 2156 43.32 39 34.19 123 29.45 1.41 12 .09 .4 2.5 MAA 2.0 97 MAR 30 2242 44.99 40 21.57 123 45.48 25.40 15 1 .11 .4 .9 MEN 2.0 97 MAR 30 2309 44.68 37 33.24 118 49.81 9.65 10 .06 .7 .8 MOR 1.3 97 MAR 30 2310 42.02 37 32.31 118 50.99 8.20 20 1 .06 .5 .6 MOR 1.6 97 MAR 31 307 51.31 37 30.90 121 40.52 4.33 11 1 .03 .3 .8 HAM 1.2 97 MAR 31 540 24.97 38 48.96 122 48.32 3.40 11 .02 .3 .6 GEY 1.3 97 MAR 31 652 49.26 36 6.63 120 40.05 3.08 24 1 .05 .3 .4 SLA 1.8 97 MAR 31 707 21.24 37 34.77 118 50.72 13.16 7 .05 4.4 5.6 MOR - 1.1 97 MAR 31 807 0.83 39 13.30 122 41.76 6.85 7 .03 .7 2.0 BAR 1.3 97 MAR 31 847 50.46 38 47.70 122 48.45 4.31 18 .04 .2 .4 GEY 1.6 97 MAR 31 1258 0.36 38 50.31 122 48.63 1.41 7 .08 .7 1.3 GEY 1.2 97 MAR 31 1348 25.87 38 49.36 122 48.25 4.00 9 .03 .3 .7 GEY 1.5 97 MAR 31 1358 46.81 38 47.82 122 48.73 4.25 9 .02 .3 .7 GEY 1.4 97 MAR 31 1500 6.42 36 46.46 121 16.82 8.35 53 1 .05 .1 .2 PAI 1.7 97 MAR 31 1554 10.34 38 49.36 122 48.00 4.02 7 .02 .4 .7 GEY 1.2 --ORIGIN TIME (UT)-- -LAT N-- --LON W-- DEPTH N N RMS ERH ERZ DUR YR MON DA HRMN SEC DEG MIN DEG MIN KM RD S SEC KM KM REMKS MAG 97 MAR 31 1621 48.02 36 57.82 121 35.80 3.07 30 1 .11 .2 .3 SAR 1.3 97 MAR 31 1808 36.61 36 33.96 121 9.33 2.75 39 1 .07 .2 .3 PIN 2.1 97 MAR 31 1849 20.71 38 47.54 122 46.71 2.49 11 .04 .2 .6 GEY 1.7 97 MAR 31 2255 16.37 39 40.47 123 33.30 1.79 18 .05 .2 .6 MAA 2.7 97 MAR 31 2257 46.25 39 40.49 123 33.05 1.25 14 .03 .3 .9 MAA 1.9 97 MAR 31 2304 46.92 36 45.79 121 16.50 6.61 13 1 .03 .4 1.0 PAI 1.1 97 MAR 31 2328 6.73 39 40.41 123 33.27 1.96 17 .04 .2 .6 MAA 2.5 97 APR 1 136 54.87 38 8.86 121 56.24 21.50 62 .14 .3 .2 JQN 3.6 97 APR 1 151 7.33 38 9.67 121 56.67 25.21 24 .15 .7 .5 JQN 1.9 97 APR 1 244 19.77 38 47.28 122 45.54 1.28 10 .04 .3 .7 GEY 1.4 97 APR 1 251 53.20 38 49.65 122 48.05 3.57 7 .02 .5 .9 GEY 1.2 97 APR 1 321 6.52 38 48.85 122 48.52 3.48 8 .02 .4 .7 GEY 1.0 97 APR 1 527 58.89 38 11.77 121 57.23 4.96 7 .03 .5 6.2 JQN - 97 APR 1 1022 32.20 38 49.22 122 47.88 4.26 19 .08 .2 .4 GEY 1.8 97 APR 1 1023 54.41 38 48.79 122 47.81 4.37 18 .02 .2 .4 GEY 1.9 97 APR 1 1328 7.75 36 33.88 121 9.44 3.39 12 .04 .3 .5 PIN 1.0 97 APR 1 1548 51.85 38 49.10 122 48.67 3.59 9 .02 .4 .6 GEY 1.5 97 APR 1 1700 21.53 37 37.14 118 53.15 3.80 18 .09 .4 .9 SHE 2.7 97 APR 1 1740 59.04 39 47.92 123 27.35 5.65 9 .06 .4 .8 MAA 1.8 97 APR 1 1808 45.50 37 36.82 118 52.64 5.09 9 .08 .6 1.6 SHE 1.4 97 APR 1 1837 18.69 38 9.36 121 56.35 20.94 33 .13 .4 .3 JQN 3.4 97 APR 1 2231 15.26 38 45.76 122 41.98 2.77 8 .06 .6 .5 GEY 1.5 97 APR 2 325 19.11 37 36.73 118 53.13 3.23 23 .11 .3 .8 SHE 3.3 97 APR 2 558 40.87 37 37.03 118 52.89 7.96 7 .06 .9 1.4 SHE 1.2 97 APR 2 717 9.30 37 36.74 118 53.24 2.15 12 .07 .4 1.4 SHE 2.0 97 APR 2 1006 17.93 37 34.19 118 51.16 8.76 15 .03 .4 .6 MOR 1.8 97 APR 2 1051 26.82 37 41.11 118 52.92 14.19 12 .21 .8 1.5 DOM 1.4 97 APR 2 1214 12.49 38 9.10 121 54.57 21.60 21 .19 .7 .3 JQN 2.4 97 APR 2 1412 34.89 38 49.14 122 50.16 0.91 16 .05 .2 .5 GEY 2.0 97 APR 2 1656 28.80 38 49.09 122 47.96 3.81 19 .05 .2 1.0 GEY 2.1 97 APR 2 1801 4.64 37 36.47 118 53.06 2.69 7 .05 .5 7.1 SHE - 1.6 97 APR 2 1930 13.08 39 24.18 123 15.88 4.94 23 .22 .5 1.7 MAA 2.3 97 APR 2 2227 9.01 38 10.08 121 55.99 22.01 26 .16 .5 .3 JQN 2.7 97 APR 3 113 57.45 37 36.67 118 53.17 2.47 15 .07 .4 1.4 SHE 2.3 97 APR 3 114 52.23 37 36.51 118 52.66 5.66 8 .07 .6 1.9 SHE 1.4 97 APR 3 314 58.52 36 41.01 121 18.74 5.78 40 .08 .2 .5 STN 2.0 97 APR 3 337 45.21 38 48.67 122 50.83 2.43 7 .03 .6 2.8 GEY 1.0 97 APR 3 437 11.83 38 53.95 122 58.56 1.64 10 .08 .3 2.3 MAA 1.7 97 APR 3 632 10.36 38 47.01 122 46.23 2.27 27 .07 .2 .5 GEY 2.4 97 APR 3 703 55.76 38 47.84 122 48.62 4.14 8 .02 .4 .8 GEY 1.2 TABLE 2. Data from National Earthquake Information Center (NEIC) UTC TIME LAT LONG DEP GS MAGS SD STA REGION AND COMMENTS HRMNSEC MB Msz USED ------------------------------------------------------------------------------- MAR 26 003233.2* 8.063S 107.714E 33N 4.7 1.0 11 JAWA, INDONESIA 011541.4 17.155N 85.462W 10G 4.6 0.9 26 CARIBBEAN SEA 022921.1? 51.06 N 179.54 E 33N 4.1 1.7 11 RAT ISLANDS, ALEUTIAN IS. 023244.3 51.378N 179.455E 33N 4.7 1.1 61 RAT ISLANDS, ALEUTIAN IS. ML 5.2 042251.2 33.372N 35.486E 10G 5.0 4.4 1.1 113 JORDAN - SYRIA REGION. ML 5.6 About 50 buildings slightly damaged in the Beirut area, Lebanon. Felt throughout Lebanon, in northern and central Israel, and in Syria. 073349.0* 15.159N 59.762W 33N 0.6 7 LEEWARD ISLANDS 083147.5 31.906N 130.532E 10G 5.6 5.9 1.3 197 KYUSHU, JAPAN. Mw 6.1 (GS), 6.1 At least 22 people injured, damage to many houses and landslides in Kagoshima Prefecture. 090459.8 31.964N 130.401E 10G 4.3 1.2 13 KYUSHU, JAPAN 091915.3 34.914N 32.919E 33N 4.3 1.0 24 CYPRUS REGION. MD 4.0 (ISK). 093138.0* 54.406N 160.889E 72* 4.2 0.8 26 NEAR EAST COAST OF KAMCHATKA 112137.6 51.219N 179.572E 33N 4.8 0.9 74 RAT ISLANDS, ALEUTIAN IS. 120658.3? 30.54 S 177.30 W 33N 5.0 1.2 12 KERMADEC ISLANDS, NEW ZEALAND 132022.1 33.725N 35.422E 10G 4.7 0.9 38 JORDAN - SYRIA REGION. ML 5.0 Felt in parts of Lebanon. Also felt in northern and central Israel. 192115.4* 20.011S 174.024W 33N 4.7 0.8 25 TONGA ISLANDS 212706.9 51.240N 179.440E 33N 4.9 0.9 95 RAT ISLANDS, ALEUTIAN IS. ML 5.2 235404.0* 51.023N 179.488E 33N 4.8 1.0 37 RAT ISLANDS, ALEUTIAN IS. ML 5.2 MAR 27 001642.2 51.241N 179.460E 33N 4.8 0.9 67 RAT ISLANDS, ALEUTIAN IS. ML 5.3 020928.3? 51.27 N 179.21 E 33N 4.3 1.5 6 RAT ISLANDS, ALEUTIAN IS. ML 4.0 041304.3* 21.984S 176.648W 138D 4.7 0.9 28 FIJI ISLANDS REGION 072034.7 22.275S 68.474W 120D 4.4 0.6 18 NORTHERN CHILE 100216.9 4.000N 82.576W 10G 5.0 4.5 1.1 63 SOUTH OF PANAMA 102305.9? 51.12 N 179.23 E 33N 4.5 1.1 21 RAT ISLANDS, ALEUTIAN IS. ML 4.5 104226.4 51.200N 179.327E 33N 5.1 5.1 1.0 95 RAT ISLANDS, ALEUTIAN IS. ML 5.4 105502.9? 51.01 N 179.02 E 33N 4.4 0.3 8 RAT ISLANDS, ALEUTIAN IS. ML 4.0 110654.4? 50.91 N 178.78 E 33N 4.4 0.9 13 RAT ISLANDS, ALEUTIAN IS. ML 4.4 111638.0* 50.961N 179.549E 33N 4.5 0.7 25 RAT ISLANDS, ALEUTIAN IS. ML 4.6 113007.0& 38.149N 121.940W 21 17 NORTHERN CALIFORNIA. MD 3.2 Felt in the Fairfield-Martinez area. 113737.2? 50.91 N 179.03 E 33N 4.3 1.1 7 RAT ISLANDS, ALEUTIAN IS. ML 4.0 120804.8* 51.064N 179.553E 33N 4.5 1.0 14 RAT ISLANDS, ALEUTIAN IS. ML 4.5 120957.0? 50.82 N 178.86 E 33N 4.5 0.6 12 RAT ISLANDS, ALEUTIAN IS. ML 4.4 121729.9? 50.91 N 178.99 E 33N 3.9 0.5 7 RAT ISLANDS, ALEUTIAN IS. ML 4.2 124124.0? 50.77 N 179.55 E 33N 4.4 0.9 12 RAT ISLANDS, ALEUTIAN IS. ML 4.2 133808.0& 38.150N 121.930W 20 15 NORTHERN CALIFORNIA. MD 3.0 Felt in the Fairfield-Martinez area. 140124.0& 38.150N 121.940W 22 13 NORTHERN CALIFORNIA. MD 3.0 Felt in the Fairfield-Martinez area. 141612.3* 39.897N 143.438E 33N 4.6 1.3 15 OFF EAST COAST OF HONSHU, JAPAN 153949.0& 38.148N 121.936W 21 21 NORTHERN CALIFORNIA. MD 3.5 Felt in the Fairfield-Martinez area. 173508.2 19.349N 145.556E 144* 4.7 0.8 29 MARIANA ISLANDS 180143.0& 38.150N 121.940W 21 12 NORTHERN CALIFORNIA. MD 3.0 Felt in the Fairfield-Martinez area. 213942.3* 51.674N 16.154E 5G 0.4 9 POLAND. ML 3.6 (VIE). 224753.0& 38.150N 121.940W 21 13 NORTHERN CALIFORNIA. MD 3.3 Felt in the Fairfield-Martinez area. 225307.0& 38.150N 121.940W 21 14 NORTHERN CALIFORNIA. MD 3.1 Felt in the Fairfield-Martinez area. MAR 28 051509.3* 4.629S 153.186E 33N 5.1 4.8 1.0 27 NEW IRELAND REGION, P.N.G. 060811.6* 51.167N 179.100E 33N 4.7 1.0 29 RAT ISLANDS, ALEUTIAN IS. 072802.0& 45.201N 120.056W 2 36 WASHINGTON-OREGON BORDER. MD 2.6 224024.3 17.702S 179.361W 554D 4.8 0.5 52 FIJI ISLANDS REGION MAR 29 094600.6 38.796N 119.613W 5G 0.8 13 CALIFORNIA-NEVADA BORDER. ML 3.3 162600.5* 31.039S 68.403W 112D 4.6 0.8 16 SAN JUAN PROVINCE, ARGENTINA MAR 30 065045.7* 51.020N 128.978W 10G 4.1 1.0 20 VANCOUVER ISLAND REGION 082401.1 33.053N 118.619W 5G 0.9 27 SOUTHERN CALIFORNIA. MD 3.5 083832.2? 15.15 S 173.21 W 33N 5.0 5.5 0.5 43 TONGA ISLANDS 120102.6* 16.761N 98.059W 33N 4.4 0.7 23 NEAR COAST OF GUERRERO, MEXICO 125744.8* 37.765N 20.054E 33N 4.7 1.0 16 IONIAN SEA 140540.6 21.916S 177.194W 221D 5.4 0.7 98 FIJI ISLANDS REGION. Mw 5.4 230557.1 51.363N 178.126W 33N 5.5 4.8 0.8 139 ANDREANOF ISLANDS, ALEUTIAN IS. Felt on Adak. MAR 31 073448.8 35.543N 111.980W 5G 0.9 21 EASTERN ARIZONA. ML 3.7 (GS). Felt at Flagstaff, Grand Canyon Village and Valle. 113928.8* 51.765N 158.037E 56D 5.0 0.7 66 NEAR EAST COAST OF KAMCHATKA 154609.9 35.503N 112.035W 5G 0.7 15 WESTERN ARIZONA. ML 3.3 (GS). Felt at Valle. 173220.0* 16.169N 92.543W 179D 4.8 0.8 30 CHIAPAS, MEXICO 182112.5* 18.031N 67.408W 5G 0.9 7 MONA PASSAGE. Felt (IV) in the Mayaguez area, Puerto Rico. APR 01 013654.0& 38.170N 121.940W 20 17 NORTHERN CALIFORNIA. MD 3.4 Felt in the Fairfield-Martinez area. 082921.0 58.388N 155.292W 10G 4.8 0.8 42 ALASKA PENINSULA 151144.9 7.600N 82.457W 10G 5.6 5.4 1.1 108 SOUTH OF PANAMA. Mw 6.1 (GS), 183332.6 17.998S 69.255W 114D 6.0 0.8 107 PERU-BOLIVIA BORDER REGION. Mw 6.2 Felt (V) at Tacna, Peru. Felt (V) at Iquique; (IV) at Arica and Putre, Chile. APR 02 000124.0* 44.446N 152.952E 33N 5.4 0.8 50 EAST OF KURIL ISLANDS 061428.5 11.321N 61.316W 33N 5.7 5.5 0.9 101 WINDWARD ISLANDS. Mw 6.2 (GS), Felt strongly on Tobago, throughout Trinidad and as far northas St. Vincent. Note: Computer users can get faster access to the Weekly Seismicity Reports in any of three ways: 1. World-Wide-Web (WWW) access: http://quake.wr.usgs.gov 2. Anonymous FTP access: quake.wr.usgs.gov (in pub/www/QUAKES/WEEKREPS) 3. Email Access: (send email to michael@andreas.wr.usgs.gov) Notes for Table 1: Origin time in the list is in GMT, in the text and on maps it is in local time. N RD: is the number of readings used to locate the event. N S: is the number of S waves in N RD. RMS SEC: is the root mean squared residual misfit for the location is seconds, the lower the better, over 0.3 to 0.5 seconds is getting bad, but this is machine, not hand timed, data. ERH: is the estimated horizontal error in kilometers. ERZ: is the estimated vertical error in kilometers. N FM: is the number of readings used to compute the magnitude. REMKS: obtuse region codes that denote the velocity model used to locate the event. DUR MAG: is the magnitude as determined from the duration of the seismograms, not the amplitude. Sort of like going to echo canyon and measuring how loud your yell is by counting echos. FIG: denotes the figure/event number in the maps posted separately.