Hi All. Curiosity got the better of me. I thought I would take a look at the area of the Loma Prieta quake for quake activity prior to the quake. It appears there was only one quake in a area with a radius of less then 1km.

I then did a search of the area of the M=3.2 quake near Hollister on 04/23/06 using the same radius. What a difference in the number of quakes inside the same radius.

It wasn’t until I used a radius of 4km that there was a substantial number of quakes in the area of the Loma Prieta quake. All that has to be done is to look for areas that have a radius of less then 4km that have no quakes, or a very small number of quakes. That would give us the possible location of the next major quake. Of course that doesn’t tell us when. Talk about looking for a needle in the haystack. Take Care…Don in creepy town

catalog=ANSS
start_time=1898/01/01,00:00:00
end_time=2006/04/24,15:58:01
minimum_magnitude=0.1
maximum_magnitude=10
event_type=E
delta=0 km to 01 km from (37.036,-121.880)
Date Time Lat Lon Depth Mag Magt Nst Gap Clo RMS SRC Event ID
----------------------------------------------------------------------------------------------
1973/10/22 04:58:03.71 37.0435 -121.8838 14.27 1.07 Md 6 120 9 0.05 NC -1017573
1989/10/18 00:04:15.20 37.0362 -121.8802 17.29 7.00 ML 79 91 1 0.08 NC 216859
1989/10/18 01:26:32.74 37.0435 -121.8785 16.62 3.22 Md 30 68 6 0.05 NC 10090822
1989/10/18 14:12:42.56 37.0312 -121.8778 16.38 0.83 Mx 9 197 9 0.02 NC 10090978
1989/10/26 06:40:15.52 37.0392 -121.8727 14.10 1.62 Md 31 54 1 0.06 NC 211384
2000/06/24 22:51:23.58 37.0378 -121.8822 12.03 0.67 Md 7 214 1 0.01 NC 30221999

catalog=ANSS
start_time=1898/01/01,00:00:00
end_time=2006/04/24,15:51:59
minimum_magnitude=0.1
maximum_magnitude=10
event_type=E
delta=0 km to 01 km from (36.795,-121.428)
Date Time Lat Lon Depth Mag Magt Nst Gap Clo RMS SRC Event ID
----------------------------------------------------------------------------------------------
1947/05/13 02:01:00.00 36.8000 -121.4200 2.70 ML BK @¥
1948/03/29 09:34:25.00 36.8000 -121.4300 2.80 ML BK @¥
1954/01/22 09:32:17.00 36.8000 -121.4200 2.60 ML BK @¥
1954/02/02 08:51:07.00 36.8000 -121.4200 2.60 ML BK @¥
1969/08/20 18:24:47.81 36.7945 -121.4170 11.38 1.70 Md 10 85 3 0.08 NC -1002982
1969/08/20 18:25:32.56 36.7943 -121.4172 11.47 1.94 Md 11 85 3 0.10 NC -1002983
1970/04/19 13:25:52.26 36.7870 -121.4300 10.34 1.05 Md 7 164 2 0.05 NC -1004406
1971/03/18 10:07:46.93 36.7932 -121.4267 10.19 1.14 Md 12 93 3 0.10 NC -1006639
1972/02/29 02:30:47.13 36.7872 -121.4233 6.38 1.29 Md 7 125 3 0.11 NC -1009744
1972/09/06 00:11:30.69 36.7927 -121.4178 10.99 1.82 Md 17 56 4 0.11 NC -1012361
1972/12/27 21:05:02.35 36.7938 -121.4178 9.59 1.30 Md 14 80 4 0.08 NC -1013927
1974/01/11 21:09:26.05 36.7952 -121.4308 10.41 1.93 Md 13 75 7 0.08 NC -1018399
1974/02/02 19:58:35.10 36.7898 -121.4297 9.62 1.14 Md 13 93 7 0.05 NC -1018614
1974/02/02 23:58:05.72 36.7915 -121.4303 9.48 1.26 Md 15 92 7 0.09 NC -1018616
1974/06/02 09:01:33.20 36.7925 -121.4295 6.97 0.82 Md 10 103 7 0.08 NC -1019796
1981/04/29 09:22:48.94 36.7878 -121.4255 6.46 0.47 Md 6 132 7 0.05 NC -1063130
1981/10/08 21:41:59.01 36.8002 -121.4308 9.30 0.98 Md 9 129 6 0.15 NC -1068437
1981/12/09 18:41:48.83 36.7943 -121.4173 5.01 0.91 Md 8 210 5 0.16 NC -1070156
1982/02/06 05:04:06.86 36.8020 -121.4330 10.50 2.10 Md 63 29 6 0.17 NC -1071847
1983/03/30 03:21:40.62 36.7958 -121.4175 10.22 0.56 Md 7 219 6 0.12 NC -1089787
1984/01/14 21:28:49.79 36.7935 -121.4310 7.27 0.97 Md 17 63 5 0.07 NC 1887
1986/03/05 10:18:36.23 36.8023 -121.4215 11.90 0.94 Md 12 104 6 0.12 NC 67586
1986/07/27 16:31:10.54 36.7883 -121.4240 7.42 0.88 Md 10 103 5 0.05 NC 77595
1987/01/31 07:33:14.10 36.7975 -121.4265 12.72 0.61 Md 4 225 7 0.01 NC -1146549
1987/04/24 18:32:32.76 36.7962 -121.4182 6.34 0.91 Md 9 202 6 0.13 NC 99176
1989/10/23 00:26:01.86 36.8028 -121.4265 10.29 0.82 Md 7 139 6 0.03 NC 228701
1989/11/06 08:48:49.99 36.8027 -121.4230 8.79 0.84 Md 11 104 6 0.11 NC 146704
1990/01/04 11:34:40.30 36.7952 -121.4188 10.85 0.83 Md 14 67 6 0.08 NC 150087
1990/05/19 21:04:07.35 36.7922 -121.4217 13.37 1.00 Md 5 199 8 0.02 NC 157936
1990/05/20 16:19:19.12 36.7988 -121.4373 12.10 0.66 Md 8 186 6 0.08 NC 158059
1990/06/03 14:26:22.65 36.7942 -121.4222 10.91 0.77 Md 14 48 5 0.15 NC 158802
1990/10/15 13:28:01.17 36.7943 -121.4248 9.19 0.89 Md 17 65 5 0.12 NC 165416
1990/11/17 12:26:32.19 36.7883 -121.4233 12.44 0.83 Md 15 63 5 0.15 NC 200252
1990/12/25 16:34:41.78 36.7868 -121.4282 8.39 0.87 Md 17 71 5 0.09 NC 203579
1991/01/02 10:28:00.92 36.7872 -121.4245 7.97 1.00 Md 30 39 5 0.15 NC 203986
1991/01/02 10:46:44.97 36.7863 -121.4273 8.21 1.17 Md 30 38 5 0.15 NC 203987
1991/01/02 10:47:26.14 36.7868 -121.4287 7.69 0.95 Md 27 39 5 0.12 NC 204383
1991/03/06 10:22:55.79 36.7962 -121.4192 8.61 0.78 Md 12 81 6 0.14 NC 207610
1991/03/08 19:43:21.76 36.8013 -121.4260 9.72 0.76 Md 16 116 6 0.15 NC 207736
1991/09/27 13:27:12.31 36.7997 -121.4267 6.49 0.48 Md 11 120 6 0.05 NC 232398
1992/03/10 08:36:20.54 36.7890 -121.4263 5.83 0.58 Md 6 217 7 0.06 NC 255791
1992/09/03 18:24:47.07 36.8020 -121.4215 18.79 0.71 Md 4 291 6 0.00 NC -1197927
1992/12/12 17:12:15.74 36.7927 -121.4195 9.36 0.80 Md 7 198 5 0.12 NC -1199890
1993/09/15 06:41:15.34 36.7997 -121.4225 9.23 0.70 Md 8 209 6 0.13 NC 30028734
1994/04/14 13:27:57.40 36.7902 -121.4220 11.04 1.13 Md 16 129 5 0.09 NC 400404
1994/09/04 06:27:11.08 36.7960 -121.4185 12.32 0.79 Md 10 169 6 0.08 NC 30056587
1994/09/05 12:49:13.90 36.7902 -121.4252 5.40 0.90 Md 10 100 7 0.06 NC 30056656
1994/09/05 13:34:48.24 36.7930 -121.4177 10.27 1.77 Md 46 35 5 0.15 NC 30056663
1995/09/16 08:06:24.29 36.7908 -121.4190 10.52 0.88 Md 8 196 5 0.11 NC 30084203
1998/04/10 11:44:00.67 36.7870 -121.4290 8.11 1.58 Md 44 30 5 0.22 NC 566834
1998/04/11 22:25:53.81 36.7888 -121.4345 5.14 1.08 Md 15 72 8 0.10 NC 567063
1998/04/12 08:56:35.95 36.7902 -121.4248 9.28 1.95 Md 59 32 5 0.15 NC 567099
1998/07/26 03:53:43.79 36.7947 -121.4173 9.50 1.16 Md 19 54 5 0.22 NC 30187135
1998/09/02 09:52:48.84 36.7958 -121.4240 11.51 0.97 Md 18 106 6 0.18 NC 30194455
1998/11/19 09:32:48.37 36.7910 -121.4183 10.21 1.27 Md 13 97 5 0.17 NC 40082631
1999/09/20 03:18:55.81 36.7955 -121.4225 11.53 2.54 Md 56 27 5 0.12 NC 21053893
1999/09/21 05:45:02.57 36.7908 -121.4288 5.02 0.88 Md 14 68 7 0.07 NC 21054140
1999/09/28 05:48:45.26 36.7982 -121.4292 11.75 1.09 Md 8 119 6 0.10 NC 40105664
1999/10/22 12:06:08.16 36.7893 -121.4328 11.10 1.42 Md 30 73 5 0.08 NC 21061980
1999/10/24 06:37:25.99 36.7910 -121.4267 10.02 1.22 Md 28 55 5 0.14 NC 21062539
1999/10/24 06:46:33.06 36.7950 -121.4172 9.95 0.79 Md 13 115 5 0.10 NC 21062541
1999/11/07 15:57:06.28 36.7940 -121.4212 8.77 1.23 Md 18 42 7 0.15 NC 21065574
1999/11/12 01:37:45.30 36.7907 -121.4270 11.04 1.51 Md 40 30 5 0.11 NC 21066468
1999/11/14 08:25:23.72 36.7940 -121.4315 10.85 1.20 Md 15 74 5 0.07 NC 21066888
1999/11/14 08:45:31.85 36.8002 -121.4295 12.12 1.03 Md 13 121 6 0.06 NC 21066890
1999/11/14 08:56:56.31 36.7917 -121.4265 10.99 1.09 Md 16 71 5 0.06 NC 21066893
1999/11/17 00:56:02.38 36.7940 -121.4285 12.10 1.26 Md 12 113 5 0.03 NC 21067449
1999/11/17 01:11:43.84 36.7995 -121.4193 9.02 0.98 Md 6 207 6 0.10 NC 51092296
1999/11/17 01:49:04.35 36.7903 -121.4233 11.54 1.65 Md 27 33 5 0.08 NC 21067453
1999/11/21 03:53:27.36 36.7925 -121.4212 10.36 1.08 Md 21 40 5 0.16 NC 21068092
1999/11/21 03:58:13.71 36.7907 -121.4227 9.50 1.49 Md 33 40 5 0.16 NC 21068094
1999/12/02 06:34:42.43 36.7958 -121.4188 10.08 1.41 Md 27 41 6 0.16 NC 21069878
1999/12/16 06:42:38.29 36.7892 -121.4318 11.00 2.51 Md 72 33 5 0.10 NC 21072045
1999/12/16 08:41:34.62 36.7955 -121.4182 9.85 1.23 Md 29 41 5 0.17 NC 21072063
2000/01/24 08:54:56.18 36.7938 -121.4212 11.86 1.25 Md 12 113 5 0.09 NC 21079603
2000/01/30 10:35:17.33 36.7982 -121.4192 11.50 1.12 Md 17 118 6 0.15 NC 21080755
2000/02/01 22:45:43.22 36.7907 -121.4198 11.28 0.95 Md 14 110 5 0.08 NC 21081115
2000/02/07 05:39:39.16 36.7883 -121.4268 9.05 1.71 Md 33 39 5 0.18 NC 51095057
2000/03/01 04:09:07.16 36.7930 -121.4282 12.03 1.18 Md 18 113 5 0.06 NC 21084795
2000/03/15 10:10:34.98 36.7972 -121.4325 11.32 1.58 Md 21 115 6 0.10 NC 51095934
2000/03/25 02:30:09.61 36.7945 -121.4260 10.55 1.24 Md 20 42 5 0.16 NC 21088238
2000/09/08 04:23:29.72 36.7885 -121.4243 4.59 1.07 Md 7 190 7 0.07 NC 21124193
2000/09/24 13:21:10.59 36.7930 -121.4210 11.69 1.15 Md 13 113 4 0.09 NC 21126714
2000/12/03 23:20:22.24 36.7877 -121.4302 10.75 0.97 Md 10 129 7 0.05 NC 21137058
2000/12/04 02:34:25.87 36.7878 -121.4247 10.61 1.12 Md 15 96 7 0.07 NC 21137082
2001/04/04 12:10:55.95 36.7948 -121.4172 11.33 0.88 Md 9 147 6 0.08 NC 21156630
2001/05/27 05:38:38.45 36.7892 -121.4195 6.62 1.13 Md 21 40 6 0.10 NC 21166689
2001/05/29 02:54:33.03 36.7865 -121.4283 10.71 1.65 Md 36 38 5 0.09 NC 21167114
2001/05/29 08:31:15.54 36.7927 -121.4188 12.30 0.99 Md 11 112 5 0.06 NC 21167159
2001/05/29 22:35:40.53 36.7952 -121.4293 11.34 0.95 Mx 6 135 6 0.02 NC 21167288
2001/06/02 19:29:45.23 36.7890 -121.4215 5.01 0.80 Md 8 128 7 0.06 NC 21167965
2001/06/13 21:36:14.26 36.7918 -121.4228 12.27 3.07 ML 72 31 5 0.12 NC 21170165
2001/09/12 18:35:00.17 36.7912 -121.4197 11.37 0.97 Md 10 119 5 0.05 NC 21193779
2002/06/06 14:39:09.02 36.8003 -121.4235 6.15 1.55 Md 39 54 6 0.16 NC 21229009
2002/07/15 08:00:23.00 36.7940 -121.4212 10.01 0.77 Md 8 113 5 0.09 NC 21235469
2003/01/18 13:40:38.65 36.7877 -121.4340 11.89 0.89 Md 11 134 5 0.05 NC 21264129
2003/01/19 00:09:18.81 36.7943 -121.4348 12.12 1.05 Md 8 165 6 0.05 NC 21264197
2004/04/18 12:23:46.35 36.7937 -121.4208 7.97 0.76 Md 15 223 5 0.33 NC 21358815
2004/06/11 00:42:54.39 36.8025 -121.4260 12.84 0.90 Md 12 115 6 0.19 NC 21370116
2004/10/22 10:05:33.81 36.7922 -121.4295 9.42 1.41 Md 12 130 5 0.13 NC 51151784
2005/03/21 14:53:47.83 36.7920 -121.4275 9.39 1.25 Md 19 111 7 0.11 NC 21446569
2005/06/01 07:14:35.24 36.7932 -121.4285 18.80 1.22 Md 7 155 12 0.13 NC 21459846
2006/04/23 20:17:07.88 36.7947 -121.4277 11.51 3.22 ML 77 28 4 0.14 NC 51170294

Number of quakes prior to the Loma Prieta quake using a 4km radius search.

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1953/06/09 01:49:57.00 37.0300 -121.9200 2.40 ML BK
1970/11/27 09:20:38.90 37.0498 -121.9142 1.85 1.86 Md 14 99 8 0.10 NC -1006091
1972/01/20 17:25:46.38 37.0530 -121.8430 12.61 1.55 Md 7 263 3 0.02 NC -1008833
1973/07/30 09:08:35.02 37.0575 -121.8507 2.49 0.79 Md 10 191 4 0.06 NC -1016579
1973/10/22 04:58:03.71 37.0435 -121.8838 14.27 1.07 Md 6 120 9 0.05 NC -1017573
1975/09/13 15:14:53.47 37.0387 -121.8640 8.20 1.12 Md 6 198 5 0.01 NC -1026327
1976/06/09 06:31:10.34 37.0707 -121.8913 14.04 1.47 Md 12 165 5 0.04 NC -1029943
1981/03/20 04:04:12.27 37.0642 -121.8547 14.68 1.51 Md 21 84 6 0.04 NC -1061499
1982/04/14 22:20:11.77 37.0708 -121.8693 6.24 1.24 Md 10 87 5 0.02 NC -1073737
1982/04/14 22:48:55.83 37.0712 -121.8710 6.44 0.84 Md 9 146 5 0.02 NC -1073739
1982/05/06 02:11:57.80 37.0648 -121.8668 4.61 0.52 Md 5 138 4 0.00 NC -1074197
1982/05/06 11:35:45.61 37.0713 -121.8715 5.46 1.30 Md 14 78 5 0.09 NC -1074207
1986/09/10 08:46:06.23 37.0538 -121.8540 15.83 0.80 Md 12 102 4 0.02 NC 81944
1987/01/08 14:52:41.99 37.0603 -121.8790 15.87 1.04 Md 21 91 6 0.03 NC 92079
1987/05/18 15:10:30.31 37.0635 -121.8823 13.41 0.87 Md 9 91 4 0.02 NC 100580
1987/09/03 14:33:17.74 37.0167 -121.8463 25.19 1.25 Md 4 286 19 0.00 NC -1151962
1988/04/25 12:15:03.52 37.0660 -121.8627 15.59 0.98 Md 14 108 5 0.05 NC 116186
1988/06/17 10:02:39.65 37.0680 -121.8995 15.58 0.65 Md 9 105 5 0.03 NC 119166
1988/12/31 23:11:31.54 37.0177 -121.8677 4.78 0.70 Md 11 140 2 0.03 NC 129447
1989/10/18 00:04:15.20 37.0362 -121.8802 17.29 7.00 ML 79 91 1 0.08 NC 216859