Hi Chris and John. Have something here for the two of you to ponder on. Below is a list of quakes taken from the ANSS catalog. You can see the criteria I used to make my search. I did 2 searches. However the searches do have some gaps in between as I used a radius of 160Km. No attempt was made to pick up the search where the last one left off.

My primary interest in the search was to see how many quakes are below 60Km in depth. I had started with 50Km, but found there were more quakes then I wanted to mess with.

They sort of follow a path that starts sort of in the NW part of the state near Miller Place and continues south to Auburn. Here is where the gap occurs. It starts again just north of the Livermore area down to Morgan Hill, through Hollister and ending in the area of San Ardo.

Assuming these quakes aren’t the results of operator error, what could most common cause for quakes at the depths these are. There is one quake with a depth of 239Km. Isn’t that a little to deep for California?

I have sent some e-mail out to see if I can find some answers. I will post what I learn. Take Care…Don in creepy town

catalog=ANSS
start_time=1976/01/01,00:00:00
end_time=2003/06/04,08:04:46
minimum_magnitude=1.0
maximum_magnitude=10
minimum_depth=60
maximum_depth=10000
event_type=E
delta=0 km to 160 km from (40.0,-122.0)
Date Time Lat Lon Depth Mag Magt Nst Gap Clo RMS SRC Event ID
----------------------------------------------------------------------------------------------
1976/08/23 23:17:47.57 38.9195 -121.0037 63.46 1.15 Md 5 113 4 0.13 NC -1031172
1980/12/20 20:38:15.28 40.1107 -123.5732 77.16 2.89 Md 7 273 10 0.26 NC -1058293
1981/12/14 20:21:22.52 39.0067 -122.6375 75.44 1.50 Md 5 123 8 0.07 NC -1070319
1982/01/10 19:56:38.30 38.9242 -122.3605 76.07 3.55 Md 5 274 18 0.24 NC -1071130
1982/03/06 20:05:44.90 40.4982 -123.3642 62.75 2.22 Md 6 278 35 0.16 NC -1072722
1982/04/08 12:22:28.26 39.2710 -123.0648 65.35 2.65 Md 8 133 16 0.25 NC -1073583
1984/05/01 20:39:44.08 40.7877 -122.4193 89.37 2.80 Md 4 160 14 0.18 NC -1114723
1985/04/03 16:55:29.10 40.4407 -122.2857 68.65 2.95 Md 14 163 28 0.04 NC 48105
1986/05/31 10:28:50.67 39.0020 -122.6342 64.15 2.30 Md 5 127 8 0.20 NC -1138626
1986/08/06 23:21:57.84 39.4223 -123.5667 71.09 4.90 Md 7 213 5 0.33 NC -1228722
1988/01/23 14:55:40.99 39.9315 -122.3507 90.83 1.59 Mx 9 242 36 0.13 NC 10086430
1988/09/30 00:39:38.09 39.8060 -121.3545 239.93 3.60 Mc 38 336 478 0.91 UW
1989/07/17 10:27:00.97 39.3683 -123.1992 94.53 2.91 Md 13 296 20 0.58 NC 140177
1989/12/20 02:51:44.11 40.3183 -122.1987 69.17 2.49 Md 17 172 14 0.06 NC 10090877
1990/01/17 18:59:26.68 39.2415 -122.8253 78.56 2.55 Md 7 173 19 0.25 NC -1170828
1998/12/12 17:01:25.94 39.6232 -121.3875 60.96 2.75 Md 7 184 7 0.70 NC 30209109
1999/01/15 08:37:58.69 39.8877 -121.8280 96.54 3.15 Md 7 175 25 0.25 NC 51069393
2000/09/13 15:52:46.40 38.9818 -122.5880 76.96 1.38 Mx 7 101 9 0.08 NC 21125114

This is the 2nd search starting just north of Livermore and ends near San Ardo. Note the two small clusters of quakes. One in 1967 and the other in 1981.

catalog=ANSS
start_time=1967/01/01,00:00:00
end_time=2003/06/04,08:38:00
minimum_magnitude=1.0
maximum_magnitude=10
minimum_depth=60
maximum_depth=10000
event_type=E
delta=0 km to 160 km from (37.2,-121.1608)
Date Time Lat Lon Depth Mag Magt Nst Gap Clo RMS SRC Event ID
----------------------------------------------------------------------------------------------
1967/07/29 18:55:51.10 35.9783 -120.9937 69.80 2.30 Mx 9 303 59 0.18 NC -1000826
1967/08/02 18:00:19.60 36.1290 -121.0765 71.27 2.30 Mx 10 288 37 0.28 NC -1000905
1967/08/04 00:51:44.51 36.0905 -121.0750 79.62 2.10 Mx 7 292 41 0.27 NC -1000931
1967/08/09 07:27:32.77 36.1453 -121.0822 70.58 2.70 Mx 10 287 35 0.38 NC -1000983
1967/08/14 18:59:33.35 35.9460 -120.9962 79.79 1.90 Mx 9 305 63 0.07 NC -1001042
1967/08/22 08:29:40.98 35.9585 -120.9733 89.81 3.00 Mx 9 304 58 0.29 NC -1001122
1967/08/22 08:35:50.50 35.9687 -120.9830 89.71 2.30 Mx 9 303 56 0.29 NC -1001123
1967/08/22 08:37:37.71 36.0572 -121.0508 70.59 2.90 Mx 9 294 45 0.31 NC -1001124
1967/08/22 08:38:23.66 36.0013 -120.9732 78.27 2.60 Mx 10 302 53 0.44 NC -1001125
1967/08/28 02:19:01.08 36.0195 -121.0220 84.59 2.00 Mx 11 298 50 0.23 NC -1001177
1973/04/07 21:13:23.13 36.8628 -121.1608 65.61 1.83 Md 9 222 22 0.75 NC -1015250
1980/01/23 07:31:02.35 36.2695 -120.9090 78.19 2.06 Md 12 255 24 1.16 NC -1050021
1980/02/08 03:45:08.99 37.7957 -121.8185 73.38 2.30 Md 16 130 2 0.12 NC -1050901
1981/01/03 04:06:53.42 36.0475 -120.3108 75.98 1.88 Md 6 253 12 0.09 NC -1058827
1981/01/05 01:16:13.99 36.1480 -120.4672 69.37 2.12 Md 5 172 15 0.29 NC -1058878
1981/01/06 22:58:53.05 36.1615 -121.0060 81.76 1.96 Md 5 212 18 0.18 NC -1058959
1981/05/10 07:50:40.55 37.3083 -121.4533 87.16 2.58 Md 6 122 13 0.06 NC -1063468
1981/12/08 16:43:17.75 37.6528 -121.3857 77.20 1.81 Md 5 224 16 0.05 NC -1070135
1981/12/16 20:11:18.26 36.6338 -120.4297 79.60 2.29 Md 10 300 33 0.35 NC -1070390
1984/03/25 12:45:43.05 36.3815 -120.5517 72.50 2.38 Md 18 221 15 1.90 NC 12169
1989/10/19 17:33:38.41 37.1025 -121.6807 60.08 1.85 Md 13 239 7 0.17 NC 272145
1993/05/08 14:12:04.01 36.3415 -120.1675 65.69 1.81 Md 6 234 13 0.30 NC -1202722
1996/03/03 13:53:37.60 37.6173 -121.9580 60.70 2.00 Md 19 293 30 1.09 NC 30098311
1999/04/29 05:30:09.82 37.1078 -121.6952 85.16 3.53 Md 4 155 29 0.12 NC 51081675