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 -- THIS IS 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 andy@pangea.stanford.edu Seismicity Report for Northern California, the Nation, and the World for the week of April 22 - 28, 1993 Data and text prepared by Steve Walter, Barry Hirshorn, and Allan Lindh U.S. Geological Survey 345 Middlefield Rd. MS-977, Menlo Park, CA 94025 Graphics by Quentin Lindh San Francisco Bay Area It's been a very quiet week here beside the Bay. For the 7-day period ending at midnight on Wednesday, April 28, 1993 the U.S. Geological Survey office in Menlo Park recorded just 13 earthquakes of magnitude one (M1) and greater within the San Francisco Bay area shown in Figure 1. Only one was as large as M2.0. This is the lowest weekly total in the past five months. By contrast, 26 earthquakes were recorded during the previous 7-day period, six of which were as large as M2. The lone M2 earthquake occurred late last Thursday night along the northern Hayward fault about 2 miles east of Berkeley (#1 in Fig. 1). The Hayward fault is generally considered to be a "locked" fault, accumulating strain rather than releasing it in numerous smaller earthquakes, as is the case on the creeping segment of the San Andreas. However, there are a couple of areas of the Hayward fault that experience occasional earthquakes in the M1-3 range. The area east of Berkeley that experienced the M2.3 last Friday night is one of those areas. The most recent comparable activity here was a pair of M2.4 events on March 24 and a M2.2 a week later, on March 31. Both the San Andreas and Calaveras faults were quiet during the week with only a few scattered M1 events. Northern & Central California The low level of activity seen in the Bay Area extended through much of the rest of northern and central California with no earthquakes as large as M3 in either region. Central California in particular was unusually quiet with only two M2.0 earthquakes, one just northeast of Coalinga, the other about 22 miles southwest of Lone Pine in the southern Sierra Nevada. Northern California saw M2 earthquakes in many of the usual places, including a pair of deep earthquakes beneath the Klamath Mountains. The first of the deep events occurred last Saturday morning, a 23 km-deep event that was located about 26 miles southeast of Eureka (#4/2). It was followed Monday morning by a 42 km-deep earthquake located about 44 miles west-southwest of Redding (#6/2). It's worth mentioning that a pair of deep earthquakes also occurred during the previous week: a 32 km-deep event on the 15th located 30 miles southeast of Eureka and a 30 km-deep event on the 19th located 45 miles east of Eureka. Cape Mendocino experienced four M2 earthquakes during the week, the largest a M2.9 last Sunday evening (#5/2). A M2.1 occurred two days earlier in the eastern Gorda Plate, about 42 miles west of Eureka (#3/2). Long Valley Caldera The increased seismicity within the caldera that has been observed during the past 4 weeks declined markedly with nothing larger than two M2.0 events on the southern rim (#2/3). These were part of a small cluster of small earthquakes that occurred Monday morning along the southern rim of the caldera, 1-2 km east of a slightly more energetic cluster during the previous week. Activity south of the caldera was also down from the previous week with a pair of M2's southeast of Mt. Crocker (#1/3) and a M2.1 near the southwest side of Convict Lake (#3/3). USA Seismicity According to information provided by the National Earthquake Information Center (NEIC), there were several notable earthquakes in the lower 48 states during the past week. Most newsworthy were a pair of moderate earthquakes south of the Grand Canyon that were widely felt in Arizona and Utah (#2/4). The first of these was a M4.8 that occurred early Sunday morning about 30 miles south of Grand Canyon Village, the main visitors center for the National Park. It was felt strongly at Flagstaff (90 miles to the south) and as far away as Phoenix and St. George Utah. It was followed early Thursday morning by a M5.5 that briefly knocked out electrical power at the National Park and that was reported to have shaken some people in Flagstaff out of their beds. No reports of injury or serious damage were immediately available. Earlier in the week, a M3.9 occurred in the Salmon River Mountains of north-central Idaho (#1/4). A slightly smaller M3.6 occurred Wednesday afternoon in the New Madrid area of the central U.S. The NEIC location places this earthquake just south of Reelfoot Lake in northwestern Tennessee (#4/4). The Planet Earth (April 19 - April 29) The planet was fairly quiet during the past week, at least with respect to seismic activity. There were no large earthquakes during the week, ie. none as large as M6.0. The largest earthquake was a Ms5.7 on the mid- ocean ridge separating the Australian and Antarctic plates (#2/5). Interestingly, a Ms5.2 occurred later in the week along the mid-ocean ridge separating the Australian and Pacific plates (#5/5). Other earthquakes of note include a M5.3 in the Kodiak Island region of Alaska that was felt at Old Harbor (#4/5), a Ms4.8 on the central East Pacific Rise (#3/5), and a Mb4.4 in the Afghanistan-Tajikistan border region (#1/5). Table 1. 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 93 APR 22 806 31.43 39 28.52 122 59.61 9.84 45 1 .11 .2 .4 BAR 2.4 93 APR 22 934 26.05 38 49.27 122 49.65 1.68 16 .07 .3 .6 GEY 1.5 93 APR 22 1015 21.97 37 39.86 118 54.16 5.22 8 .04 .6 .8 DOM 1.2 93 APR 22 1126 7.15 38 47.74 122 48.39 4.95 8 .10 1.4 1.1 GEY 1.1 93 APR 22 1242 36.02 37 33.98 118 28.74 11.32 22 1 .08 .3 .6 CHV 1.5 93 APR 22 1359 56.26 37 38.19 118 53.23 5.57 7 .09 1.4 1.7 SMO 1.9 93 APR 22 1453 23.77 38 51.24 122 50.97 4.17 10 2 .08 .5 1.5 GEY 1.4 93 APR 22 1540 46.55 37 39.30 118 54.36 5.01 18 .11 .4 .6 DOM 1.8 93 APR 22 1546 23.60 37 0.67 121 27.80 7.77 20 .07 .3 .7 CYS 2.5 93 APR 22 1606 5.97 37 39.54 118 54.38 4.49 10 1 .08 .5 .6 DOM 1.0 93 APR 22 1713 8.65 37 28.09 118 50.08 7.20 30 3 .10 .5 1.1 MOR 1.7 93 APR 22 2206 57.31 37 39.10 118 54.48 5.65 19 2 .11 .4 .5 DOM 1.5 93 APR 22 2249 23.07 37 38.59 118 46.87 9.76 8 .14 5.3 5.1 EMO 1.2 93 APR 22 2352 56.42 37 31.15 118 48.29 14.38 20 .09 .5 1.0 MOR 1.4 93 APR 23 2 11.48 38 48.26 122 46.29 1.75 9 .15 .9 1.6 GEY 1.5 93 APR 23 311 21.33 38 48.85 122 48.53 4.25 11 .04 .3 .4 GEY 1.3 93 APR 23 315 40.43 37 25.97 118 37.23 10.48 31 3 .09 .3 .6 RVL 1.6 93 APR 23 329 32.12 38 47.32 122 46.32 6.55 9 .08 .6 1.1 GEY 1.2 93 APR 23 432 57.50 40 8.58 123 51.12 20.78 9 1 .17 1.0 1.3 MEN 1.4 93 APR 23 601 45.39 37 38.97 118 52.10 8.60 12 2 .03 .5 .8 SMO .9 93 APR 23 757 24.65 39 52.42 122 25.40 31.06 9 2 .17 1.7 3.7 SAC 1.7 93 APR 23 833 32.98 36 22.23 120 44.29 12.28 18 1 .11 .5 .4 CRV 1.4 93 APR 23 941 30.71 36 47.34 121 28.15 5.05 19 1 .16 .4 .7 SJB 1.0 93 APR 23 1111 4.56 36 11.50 120 45.19 7.43 27 3 .16 .5 .6 BIT 1.8 93 APR 23 1214 52.62 39 37.31 123 38.94 0.01 17 1 .16 .6 2.6 PAR- 1.6 93 APR 23 1733 47.50 37 40.91 119 26.07 18.46 16 3 .14 .5 2.6 KAI 2.1 93 APR 23 1800 39.99 38 47.82 122 48.24 3.04 12 .05 .3 .6 GEY 1.7 93 APR 23 1819 18.69 38 4.09 120 24.57 0.87 8 .08 .6 9.6 YOS - 1.5 93 APR 23 1823 27.19 38 48.73 122 48.07 2.72 8 .02 .4 .5 GEY 1.1 93 APR 23 2017 46.62 40 17.50 124 28.52 20.91 10 1 .12 1.7 .6 MEN 2.0 93 APR 23 2255 38.27 39 58.66 120 43.15 0.03 23 .29 2.2 4.5 WAK * 2.2 93 APR 24 202 31.90 35 49.57 120 22.40 6.49 12 .02 .3 .4 GOL 1.3 93 APR 24 317 30.85 36 44.69 121 27.14 7.89 45 .22 .4 .8 SJB 1.8 93 APR 24 409 34.82 40 17.34 124 23.33 21.32 13 1 .10 1.3 .4 MEN 1.8 93 APR 24 416 51.39 40 55.55 124 57.31 5.97 13 .10 3.4 4.8 DEL 2.1 93 APR 24 441 4.51 35 51.79 120 24.20 5.40 19 2 .07 .4 .4 GOL 1.4 93 APR 24 622 41.33 37 52.00 122 14.30 10.59 52 4 .18 .2 .7 HAY 2.4 93 APR 24 806 46.11 36 44.26 121 5.25 1.27 22 .30 .7 5.2 ORT 1.2 93 APR 24 902 46.88 37 35.26 121 48.67 8.97 19 1 .10 .3 .6 SUN 1.1 93 APR 24 1114 13.22 40 23.57 124 14.22 11.18 16 1 .07 .2 .3 MEN 1.6 93 APR 24 1308 49.80 36 28.58 121 0.38 1.40 17 .10 .3 1.1 BIT 1.3 93 APR 24 1352 10.12 37 37.92 118 48.75 3.58 7 1 .02 2.1 1.8 HCF 1.1 93 APR 24 1506 7.38 37 38.20 118 48.52 3.97 8 2 .06 1.2 1.2 HCF 1.3 93 APR 24 1513 48.58 37 37.94 118 51.96 3.63 17 2 .09 .3 .7 SMO 1.8 93 APR 24 1539 3.86 37 36.97 118 51.34 14.75 7 .15 2.811.7 SMO - 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 93 APR 24 1656 49.87 37 39.66 118 50.94 5.66 11 .06 .6 .7 HCF 1.2 93 APR 24 1814 11.73 36 22.39 120 56.91 7.19 28 1 .06 .2 .6 BIT 1.9 93 APR 24 1814 24.77 38 48.48 122 49.58 1.88 7 .04 .3 .6 GEY 1.2 93 APR 24 1848 51.12 40 40.82 123 42.05 23.08 19 2 .08 .3 .4 EUR 2.0 93 APR 24 1908 10.20 37 31.97 121 40.18 4.41 13 .06 .3 .7 HAM 1.0 93 APR 24 1915 17.31 37 33.55 118 28.04 10.40 12 1 .04 .4 .7 CHV 1.1 93 APR 24 1931 31.20 37 33.51 118 49.28 11.55 21 .13 .5 .9 MOR 1.8 93 APR 24 2235 40.68 38 50.23 122 49.07 3.24 9 .03 .6 .8 GEY 1.3 93 APR 24 2354 20.49 37 23.56 121 44.55 3.37 10 1 .09 .5 1.1 ALU 1.3 93 APR 25 5 24.66 36 12.63 120 18.80 10.39 30 .12 .3 .4 COA 2.1 93 APR 25 19 6.60 38 47.92 122 48.59 4.78 13 .10 .4 .7 GEY 1.4 93 APR 25 31 22.81 37 34.50 118 51.56 9.70 16 .13 .5 .9 MOR 1.1 93 APR 25 49 21.22 36 58.15 121 35.89 2.00 35 .16 .3 .6 SAR 1.5 93 APR 25 401 31.93 40 2.05 122 52.17 4.93 7 2 .13 .8 5.2 KLA 1.2 93 APR 25 406 32.31 39 29.28 122 0.40 18.04 11 .06 .5 1.1 SAC 1.7 93 APR 25 511 47.24 37 37.92 118 51.99 9.56 13 1 .13 .6 .9 SMO 1.5 93 APR 25 626 28.98 36 0.93 120 33.46 4.12 8 2 .03 .4 1.4 SLA 1.2 93 APR 25 923 11.19 40 24.21 124 33.92 13.97 14 1 .10 1.4 .4 MEN 1.8 93 APR 25 937 32.18 36 33.53 121 5.44 9.62 18 2 .08 .4 .8 BVL .9 93 APR 25 1018 31.81 39 19.69 122 49.47 9.11 46 1 .15 .3 1.0 BAR 2.4 93 APR 25 1043 36.02 37 36.74 118 28.43 10.45 18 1 .09 .4 .8 CHV 1.4 93 APR 25 1157 1.25 37 38.46 118 52.70 9.11 12 1 .07 .6 1.1 SMO 1.0 93 APR 25 1211 50.65 37 33.87 118 46.95 6.95 11 1 .08 .5 .9 MOR .9 93 APR 25 1354 41.58 38 47.58 122 46.59 2.91 10 .09 .4 .9 GEY 1.1 93 APR 25 1708 25.88 39 20.96 122 53.58 7.63 17 .04 .3 1.3 BAR 1.6 93 APR 25 1823 48.21 39 19.67 122 49.72 5.26 12 .04 .3 2.5 BAR- 1.6 93 APR 25 2147 23.58 37 28.86 118 48.76 8.66 31 2 .12 .4 .9 MOR 2.2 93 APR 25 2242 52.66 37 37.60 118 52.11 2.60 16 .10 .3 .5 SMO 1.9 93 APR 25 2301 16.88 37 28.85 118 48.73 8.36 34 2 .11 .4 1.0 MOR 2.2 93 APR 26 104 31.31 36 29.85 121 4.48 4.54 19 1 .05 .3 1.1 BIT 1.1 93 APR 26 119 36.37 40 24.71 124 25.51 10.47 12 1 .06 .9 .4 MEN 1.4 93 APR 26 334 19.09 40 17.94 124 16.71 10.18 23 2 .14 .4 .2 MEN 2.8 93 APR 26 605 19.20 38 48.83 122 48.31 4.49 40 .15 .3 .5 GEY 2.2 93 APR 26 614 47.10 38 48.92 122 48.00 4.69 26 .12 .3 .6 GEY 1.8 93 APR 26 614 58.38 38 48.97 122 48.30 3.88 10 .02 .3 .5 GEY 2.1 93 APR 26 813 52.21 37 37.39 118 52.01 4.24 8 .09 .5 1.4 SMO 1.3 93 APR 26 930 45.71 36 14.26 120 21.02 9.81 23 .15 .4 .4 COA 1.4 93 APR 26 949 14.51 38 50.42 122 49.30 3.49 17 .10 .3 1.2 GEY 1.7 93 APR 26 958 4.36 36 28.33 121 47.52 17.66 13 1 .07 1.0 .8 SUR 1.2 93 APR 26 1152 22.36 37 6.66 121 49.42 3.20 24 .09 .3 .4 LOM 1.1 93 APR 26 1200 23.97 37 38.14 118 48.57 3.42 9 .05 .4 .9 HCF 1.3 93 APR 26 1237 4.30 37 37.37 118 51.96 3.89 9 .10 .5 1.3 SMO 1.6 93 APR 26 1333 24.86 40 17.38 123 7.17 42.16 37 2 .16 .3 1.0 KLA 2.6 93 APR 26 1333 26.66 37 37.30 118 52.16 2.87 33 1 .12 .3 .4 SMO 2.0 93 APR 26 1405 30.96 39 55.71 120 52.26 5.15 17 2 .34 2.113.5 WAK * 2.1 --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 93 APR 26 1457 45.92 38 32.66 118 22.08 7.97 11 .4027.825.0 NEV - 2.2 93 APR 26 1458 13.36 38 18.56 118 25.65 8.05 10 .35 9.029.4 MOL - 1.9 93 APR 26 1520 23.26 37 37.23 118 52.12 3.03 32 1 .13 .3 .5 SMO 2.1 93 APR 26 1623 3.90 37 39.14 118 54.60 6.27 9 .03 .6 .9 DOM 1.1 93 APR 26 1658 26.10 37 28.48 118 48.82 9.17 18 .08 .6 1.1 MOR 1.2 93 APR 26 1727 29.76 37 37.23 118 52.30 3.09 13 .05 .3 .4 SMO 1.5 93 APR 26 1727 43.04 37 37.16 118 52.18 3.32 9 .04 .4 .6 SMO 1.7 93 APR 26 1737 14.57 37 37.45 118 52.21 3.07 7 .04 .5 .7 SMO 1.3 93 APR 26 1738 31.64 37 37.47 122 0.83 12.18 21 2 .11 .4 .8 HAY 1.5 93 APR 26 1851 46.05 37 36.67 118 55.35 4.19 10 .05 .5 .7 SHE .9 93 APR 26 2020 8.26 36 48.73 121 31.82 6.74 48 1 .16 .3 .4 SJB 1.5 93 APR 26 2130 24.63 38 48.70 122 48.54 4.26 9 .03 .4 .6 GEY 1.3 93 APR 26 2130 57.82 38 48.64 122 48.23 5.68 12 .13 .5 .9 GEY 1.5 93 APR 26 2137 18.84 37 37.13 118 51.73 4.87 8 .03 .5 .7 SMO 1.0 93 APR 26 2339 57.91 37 37.86 118 48.67 3.41 16 .10 .4 .8 HCF 1.4 93 APR 27 152 10.50 37 38.78 118 55.76 8.80 10 .09 .6 1.4 SMO 1.2 93 APR 27 237 19.97 37 38.91 118 55.69 5.86 10 .10 .5 1.1 SMO 1.1 93 APR 27 954 43.80 39 17.43 123 14.07 6.67 19 1 .14 .3 1.4 MAA 1.4 93 APR 27 1448 49.60 36 24.85 118 22.53 0.19 19 1 .10 .5 1.2 WWF 2.4 93 APR 27 1549 35.86 38 47.79 122 46.45 2.37 10 .06 .3 .6 GEY 1.4 93 APR 27 2031 24.43 37 19.51 118 17.31 11.91 24 .14 .9 1.2 OWV 1.7 93 APR 27 2047 26.21 36 52.29 120 49.36 0.73 12 .11 1.1 .8 ORT 2.2 93 APR 27 2130 33.81 38 50.44 122 49.49 2.07 9 .07 .5 .8 GEY 1.4 93 APR 27 2203 48.15 36 35.15 121 11.04 3.44 8 .03 .4 .5 PIN 1.0 93 APR 27 2214 34.72 37 56.57 121 32.61 12.66 33 3 .21 .5 1.2 JQN 1.9 93 APR 27 2302 33.93 40 17.50 124 22.42 13.79 18 1 .10 .7 .4 MEN 2.2 93 APR 27 2333 51.67 37 37.74 118 52.05 3.54 11 .10 .4 .9 SMO 1.6 93 APR 28 19 17.25 37 15.34 118 39.16 6.62 25 3 .07 .5 1.8 KAI 1.6 93 APR 28 20 16.85 36 16.38 120 24.98 9.95 25 1 .10 .4 .6 COA 2.0 93 APR 28 26 56.39 37 48.80 122 2.67 12.24 21 2 .07 .3 .5 CON 1.4 93 APR 28 255 6.19 38 50.18 122 48.05 0.04 13 .15 .4 1.9 GEY * 1.7 93 APR 28 408 31.01 38 47.74 122 47.24 0.02 12 .11 .4 1.7 GEY * 1.7 93 APR 28 535 45.05 40 18.76 124 30.04 10.98 14 1 .13 1.1 .5 MEN 2.3 93 APR 28 727 38.80 35 44.38 118 3.16 4.07 10 1 .08 .4 2.1 WWF- 1.6 93 APR 28 744 29.63 37 39.82 118 53.80 5.49 8 .05 .8 .9 DOM 1.1 93 APR 28 811 19.02 37 35.88 118 51.62 8.22 10 .08 1.4 1.0 MOR 1.1 93 APR 28 943 45.35 38 49.05 122 46.31 0.89 15 .09 .3 .7 GEY 2.0 93 APR 28 943 52.13 37 35.22 118 52.09 7.35 20 .12 .5 .5 MOR 2.1 93 APR 28 945 38.08 38 49.29 122 45.95 0.11 8 .04 .3 .9 GEY 1.5 93 APR 28 946 13.46 38 48.88 122 46.46 1.41 32 .12 .2 .4 GEY 2.2 93 APR 28 1158 55.16 38 49.32 122 47.37 0.98 8 .04 .3 .6 GEY 1.5 93 APR 28 1243 49.05 37 38.13 118 51.78 3.96 20 1 .07 .3 .4 SMO 1.7 93 APR 28 1400 22.51 38 49.24 122 45.98 0.06 10 .10 .4 .9 GEY * 1.6 93 APR 28 1538 41.34 38 50.05 122 47.43 0.60 11 .15 .4 1.2 GEY 1.7 93 APR 28 1542 49.14 38 50.04 122 47.49 1.64 9 .06 .3 .7 GEY 1.3 --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 93 APR 28 1543 15.78 38 48.11 122 46.63 4.03 8 .01 .4 .7 GEY 1.2 93 APR 28 2002 42.68 37 31.96 118 48.47 14.79 13 .11 .7 1.4 MOR 1.5 93 APR 28 2034 0.71 37 38.14 118 51.94 3.61 9 .08 .5 1.0 SMO 1.7 93 APR 28 2038 50.17 37 38.64 118 52.17 0.09 8 .19 .5 7.1 SMO * 1.3 93 APR 28 2115 44.54 37 37.99 118 52.37 2.20 8 .06 .3 .6 SMO 1.2 93 APR 28 2317 6.70 37 31.66 118 25.53 8.96 12 .09 .6 .9 CHV 1.2 93 APR 29 15 58.46 37 37.97 118 52.21 2.18 12 .18 .4 .7 SMO 1.8 93 APR 29 40 37.39 37 29.36 118 31.67 12.05 23 .06 .3 .6 CHA 2.2 93 APR 29 452 28.15 38 41.11 122 46.22 5.59 10 .14 .5 1.3 NAP 1.1 93 APR 29 647 48.46 37 30.59 118 45.48 1.28 16 .15 .910.6 WCN - 1.7 93 APR 29 653 6.12 37 31.35 118 45.76 6.86 18 .12 .5 1.8 WCN 1.9 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 -------------------------------------------------------------------------------- APR 20 015804.4? 33.34 N 141.02 E 33N 4.7 1.4 10 OFF EAST COAST OF HONSHU, JAPAN 031100.6? 36.69 N 71.90 E 33N 4.4 0.9 12 AFGHANISTAN-TAJIKISTAN BORD REG. 033838.6* 17.943N 62.704W 33N 4.4 0.8 23 LEEWARD ISLANDS 064450.6& 59.410N 153.160W 109 69 SOUTHERN ALASKA. . 081120.8? 54.33 S 144.08 E 10G 5.7 1.5 12 WEST OF MACQUARIE ISLAND 094306.1* 3.803N 128.405E 73? 4.7 0.8 9 NORTH OF HALMAHERA, INDONESIA 134212.1* 34.283N 26.451E 33N 4.3 1.4 16 CRETE. MD 4.3 (HLW). 161128.1& 60.110N 152.880W 111 3.8 86 SOUTHERN ALASKA. . 162620.4 20.586S 178.818W 592D 5.6 0.8 115 FIJI ISLANDS REGION 185642.8* 83.653N 113.823E 10G 4.1 1.3 15 NORTH OF SEVERNAYA ZEMLYA 221723.8? 7.05 N 125.09 E 51? 4.6 1.4 16 MINDANAO, PHILIPPINE ISLANDS 222449.5? 1.89 N 125.87 E 139? 4.6 0.6 6 NORTHERN MOLUCCA SEA APR 21 003807.0& 61.270N 150.160W 38 52 SOUTHERN ALASKA. . ML 2.7 125825.4 0.011N 123.461E 96? 5.3 1.1 39 MINAHASSA PENINSULA, SULAWESI 174157.4* 52.242N 170.043W 33N 4.5 1.4 42 FOX ISLANDS, ALEUTIAN ISLANDS 203636.7* 51.636N 175.792W 43D 4.8 1.3 37 ANDREANOF ISLANDS, ALEUTIAN IS. Felt strongly on Adak. APR 22 005939.6* 8.782S 108.048W 10G 4.9 4.8 1.0 50 CENTRAL EAST PACIFIC RISE 010538.1 4.031S 102.429E 70 5.5 0.9 40 SOUTHERN SUMATERA, INDONESIA 031849.6* 25.407S 179.598E 509D 4.8 0.8 42 SOUTH OF FIJI ISLANDS 060250.2& 60.890N 149.810W 26 51 KENAI PENINSULA, ALASKA. . ML 2.6 (AEIC), 2.6 (PMR). 062105.0* 4.552N 76.228W 100G 4.5 0.9 28 COLOMBIA 063612.4* 2.415N 127.274E 75D 5.2 1.1 17 NORTHERN MOLUCCA SEA 110329.5* 32.055N 115.108W 5G 1.2 16 CALIF.-BAJA CALIF. ML 3.9 123156.3 10.669N 62.607W 100G 4.5 0.8 39 NEAR COAST OF VENEZUELA. MD 4.1 124554.9 56.891N 154.654W 35D 5.3 1.2 172 KODIAK ISLAND REGION. Felt (I) at Old Harbor. 152203.2& 62.500N 149.930W 4 2.6 43 CENTRAL ALASKA. . ML 3.0 160806.9* 24.280S 67.080W 171? 4.7 0.8 8 CHILE-ARGENTINA BORDER REGION 162527.3* 52.906N 170.247W 111* 4.3 1.1 33 FOX ISLANDS, ALEUTIAN ISLANDS 163354.9? 19.22 S 177.98 W 500G 4.8 0.4 10 FIJI ISLANDS REGION 172018.2% 33.141S 70.255W 10G 0.2 8 CHILE-ARGENTINA BORDER, MD 3.7 180339.2? 16.18 S 167.58 E 33N 5.2 4.4 1.0 9 VANUATU ISLANDS 195315.3? 32.47 S 71.60 W 50G 0.4 8 COAST OF CENTRAL CHILE. MD 3.8 201854.0 35.696N 137.495E 7 4.2 1.4 31 EASTERN HONSHU, JAPAN 210930.4& 61.420N 151.450W 90 68 SOUTHERN ALASKA. . 221519.1* 53.413S 159.245E 10G 5.3 5.2 1.3 15 MACQUARIE ISLANDS REGION 233441.1* 47.481N 152.534E 110* 4.7 0.9 31 KURIL ISLANDS APR 23 095107.8 34.088N 116.860W 5G 0.7 7 SOUTHERN CALIFORNIA. ML 2.8 121445.2 44.501N 114.784W 5G 0.6 56 WESTERN IDAHO. ML 3.9 (GS), 150817.6& 61.630N 150.670W 53 63 SOUTHERN ALASKA. . ML 2.9 160116.2? 32.21 S 70.26 W 120G 0.4 8 CHILE-ARGENTINA BORDER, MD 3.7 164913.2? 32.06 S 70.11 W 130G 0.4 8 CHILE-ARGENTINA BORDER, MD 3.6 APR 24 083607.1% 33.468S 70.206W 110G 0.2 9 CHILE-ARGENTINA BORDER, MD 3.4 090617.7% 42.571N 143.716E 75? 0.5 8 HOKKAIDO, JAPAN REGION 092357.4? 32.13 S 69.91 W 130G 0.3 9 MENDOZA PROV.,ARGENTINA, MD 4.2 095421.2 17.613S 179.765E 599D 5.5 0.8 100 FIJI ISLANDS 104920.5* 20.452S 178.728W 600G 4.8 1.0 19 FIJI ISLANDS REGION 154536.9* 11.825N 124.049E 33N 4.5 0.7 10 LEYTE, PHILIPPINE ISLANDS 175323.7% 32.819S 70.910W 70G 0.2 8 CHILE-ARGENTINA BORDER, MD 3.2 203012.1* 27.367N 57.837E 33N 4.5 0.8 16 SOUTHERN IRAN APR 25 000708.8* 15.377S 173.216W 33N 5.3 5.6 1.0 42 TONGA ISLANDS 092950.5 35.641N 112.157W 10G 4.8 1.2 47 WESTERN ARIZONA. Felt at Flagstaff, Grand Canyon Village and Phoenix. Also felt at St. George, Utah. 132957.6% 33.020S 71.073W 33N 0.3 8 COAST OF CENTRAL CHILE. MD 3.2 APR 26 033405.8 60.709N 151.936W 105 0.8 62 KENAI PENINSULA, ALASKA APR 27 071808.4 34.087N 117.190W 10G 1.1 9 SOUTHERN CALIFORNIA. ML 3.0 (GS). Felt at San Bernardino. APR 28 223959 Q 36.1 N 89.4 W 10G 0.7 7 NEW MADRID, MISSOURI REGION. mbLg 3.6 (GS). APR 29 082101 Q 35.6 N 112.1 W 10G 5.5 1.3 76 WESTERN ARIZONA Notes: 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.