I would like to concentrate a bit more on the Nevada swarm, because if what I am suggesting is correct (remember this is just a theory) than the
implications are huge. It changes how we look at it.
I think that first we need to go back and check out the foreshocks of the Japan 9.1 quake. That system is the closest to ours (cascadian subduction
zone) and that we have such recent history to look at and compare is very unique.
This is what I have been able to come up with. First, let's look at the day of the 7.2 foreshock on 3/9/11
5.3 2011/03/09 08:02:36 38.606 143.103 15.4 OFF THE EAST COAST OF HONSHU, JAPAN
5.1 2011/03/09 07:56:27 38.849 142.929 10.7 NEAR THE EAST COAST OF HONSHU, JAPAN
5.0 2011/03/09 07:13:48 38.246 143.108 9.9 OFF THE EAST COAST OF HONSHU, JAPAN
5.1 2011/03/09 06:25:12 38.299 143.067 10.8 OFF THE EAST COAST OF HONSHU, JAPAN
4.9 2011/03/09 06:12:13 38.681 143.022 10.0 OFF THE EAST COAST OF HONSHU, JAPAN
4.7 2011/03/09 05:27:06 37.830 145.135 10.0 OFF THE EAST COAST OF HONSHU, JAPAN
5.3 2011/03/09 04:45:54 38.543 142.740 27.0 NEAR THE EAST COAST OF HONSHU, JAPAN
5.7 2011/03/09 04:37:03 38.666 142.991 25.5 NEAR THE EAST COAST OF HONSHU, JAPAN
5.2 2011/03/09 04:32:10 38.727 143.001 32.1 OFF THE EAST COAST OF HONSHU, JAPAN
4.8 2011/03/09 04:15:39 38.857 142.658 12.6 NEAR THE EAST COAST OF HONSHU, JAPAN
5.2 2011/03/09 04:05:53 38.870 142.420 10.9 NEAR THE EAST COAST OF HONSHU, JAPAN
5.0 2011/03/09 03:19:00 38.795 142.962 19.9 NEAR THE EAST COAST OF HONSHU, JAPAN
5.2 2011/03/09 03:08:35 38.339 143.097 24.4 OFF THE EAST COAST OF HONSHU, JAPAN
5.6 2011/03/09 02:57:16 38.402 142.825 17.5 NEAR THE EAST COAST OF HONSHU, JAPAN
7.2 2011/03/09 02:45:18 38.510 142.792 14.1 NEAR THE EAST COAST OF HONSHU, JAPAN
4.7 2011/03/09 12:03:17 38.343 143.105 10.4 OFF THE EAST COAST OF HONSHU, JAPAN
5.1 2011/03/09 11:27:49 38.573 143.146 12.0 OFF THE EAST COAST OF HONSHU, JAPAN
4.7 2011/03/09 10:13:36 38.724 143.099 10.1 OFF THE EAST COAST OF HONSHU, JAPAN
4.8 2011/03/09 08:55:38 38.667 143.055 15.6 OFF THE EAST COAST OF HONSHU, JAPAN
I guess I really didn't pay too much attention to the depth of these quakes. I think that perhaps others like myself did not think of these as
foreshocks to the subduction zone quake because of the depths. They are not that deep.
Here is a very long list of quakes that fateful day, leading up to the later upgraded 9.0:
MAP 5.3 2011/03/11 22:42:59 37.627 143.801 27.4 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 22:36:57 37.097 143.796 25.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.6 2011/03/11 22:29:42 38.285 142.636 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.7 2011/03/11 22:08:14 40.152 142.219 47.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 21:41:58 37.279 142.351 10.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/11 21:34:25 37.401 141.236 37.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 21:00:46 39.048 142.477 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 20:41:24 37.675 143.698 25.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 20:36:10 37.838 142.847 24.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 20:34:40 36.993 140.985 25.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 20:23:44 35.818 141.583 24.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 20:11:23 39.025 142.645 8.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.6 2011/03/11 19:46:49 40.472 139.070 10.0 NEAR THE WEST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 19:45:24 37.653 141.548 25.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 19:31:56 36.962 138.367 10.3 EASTERN HONSHU, JAPAN
MAP 5.5 2011/03/11 19:24:29 35.770 140.639 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 19:02:59 39.372 142.900 24.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 18:59:15 37.037 138.355 10.0 NEAR THE WEST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 18:55:15 35.814 141.657 24.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 18:44:06 36.858 141.029 25.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 18:43:14 40.139 143.061 89.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 18:39:34 37.916 143.055 1.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 18:17:06 36.218 141.685 25.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/11 18:11:24 37.118 142.160 13.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.7 2011/03/11 18:02:39 36.793 143.212 24.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 17:50:01 37.648 144.991 25.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 17:32:14 37.137 144.572 24.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 17:30:48 37.418 141.099 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 17:23:57 36.015 141.888 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 17:17:00 37.111 144.145 26.4 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/11 17:15:00 39.016 142.517 51.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 17:12:41 37.564 144.069 25.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 16:55:53 37.779 143.171 25.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 16:34:22 39.376 143.405 40.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 16:20:52 36.157 141.877 25.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 16:11:27 39.463 143.577 9.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 16:04:53 39.236 144.320 25.5 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 15:55:23 36.626 142.162 24.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 15:50:59 37.409 142.217 24.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 15:46:02 36.022 141.958 19.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 15:42:05 36.066 141.515 15.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 15:36:16 38.907 142.722 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 15:32:34 37.216 142.233 25.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 15:19:38 36.233 141.856 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 15:13:15 35.997 141.796 18.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 15:01:39 39.082 142.383 26.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 14:56:16 35.979 141.367 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 14:54:04 35.919 141.819 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 14:44:08 36.655 140.769 25.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 14:26:31 37.431 142.254 13.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 14:20:20 37.947 143.183 25.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 14:10:39 37.575 141.963 25.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 14:00:38 36.151 140.845 30.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 13:58:50 36.681 141.776 25.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 13:55:28 38.039 142.831 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 13:48:38 38.426 143.061 25.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 13:43:10 38.972 144.209 25.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/11 13:42:27 37.410 142.009 25.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 13:34:36 36.249 141.850 35.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 13:31:55 39.152 142.837 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 13:16:50 36.304 141.730 30.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 13:15:45 37.393 141.882 30.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 13:02:43 36.755 141.885 30.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 12:59:21 36.128 141.768 24.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 12:54:52 38.502 142.120 36.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 12:49:01 36.158 141.711 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 12:34:22 36.912 143.736 39.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 12:33:19 38.374 142.590 29.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 12:28:45 36.166 141.664 29.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 12:24:37 36.525 141.707 27.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 12:12:53 38.052 142.542 21.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 12:04:16 36.351 142.700 38.4 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 11:56:16 36.356 141.504 39.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 11:54:02 36.982 142.535 45.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 11:46:47 36.034 141.055 47.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 11:44:28 36.709 142.231 31.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.5 2011/03/11 11:36:39 39.276 142.521 11.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/11 11:21:02 35.759 140.913 25.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 11:16:51 36.614 141.894 36.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 11:13:12 36.451 141.789 18.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 11:10:58 35.534 141.856 27.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 11:00:51 37.813 141.481 28.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/11 10:58:06 39.060 142.213 30.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/11 10:52:08 38.534 143.346 29.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 10:45:46 38.466 143.591 41.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 10:35:36 37.044 141.298 25.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 10:28:44 39.447 143.531 29.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 10:20:27 36.966 142.289 21.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.0 2011/03/11 10:10:35 39.248 142.779 28.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:59:57 36.703 142.207 41.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 09:47:02 39.685 142.938 29.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:42:22 39.438 142.749 30.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 09:37:08 35.877 141.585 29.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 09:09:15 37.717 143.267 36.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 09:04:10 37.299 142.655 30.5 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:00:20 37.056 141.966 20.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 08:52:26 36.763 141.910 35.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 08:46:48 37.421 142.453 37.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 08:40:56 37.465 141.122 38.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 08:31:08 37.428 141.200 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.5 2011/03/11 08:19:24 36.200 142.000 19.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 08:15:41 37.034 144.612 27.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 08:12:05 36.606 141.557 19.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 08:10:31 36.394 140.631 30.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 08:01:59 37.071 142.734 22.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 07:56:16 37.130 142.305 34.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/11 07:54:45 37.742 141.565 45.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 07:42:55 36.406 141.919 29.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 07:38:27 39.250 142.783 29.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 07:28:12 36.802 141.911 24.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 07:25:33 37.916 144.621 15.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 07:14:59 36.648 141.811 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 07:13:47 36.051 142.347 28.5 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 07:11:00 37.899 142.734 30.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 06:57:15 35.758 140.992 30.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 06:48:47 37.993 142.764 22.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 7.1 2011/03/11 06:25:51 38.106 144.553 19.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.8 2011/03/11 06:15:40 36.186 141.192 35.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.4 2011/03/11 06:07:22 36.401 141.862 35.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.4 2011/03/11 06:06:11 39.025 142.316 25.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 8.9 2011/03/11 05:46:24 38.322 142.369 24.4 NEAR THE EAST COAST OF HONSHU, JAPAN
Note that the overall depths are deeper? Is that what we should be looking for? Swarms of quakes deepening and intensifying?
Here is the final and official listing of the 9.0 on USGS:
Magnitude 9.0
Date-Time Friday, March 11, 2011 at 05:46:23 UTC
Friday, March 11, 2011 at 02:46:23 PM at epicenter
Time of Earthquake in other Time Zones
Location 38.322°N, 142.369°E
Depth 32 km (19.9 miles) set by location program
Region NEAR THE EAST COAST OF HONSHU, JAPAN
Distances 129 km (80 miles) E of Sendai, Honshu, Japan
177 km (109 miles) E of Yamagata, Honshu, Japan
177 km (109 miles) ENE of Fukushima, Honshu, Japan
373 km (231 miles) NE of TOKYO, Japan
Location Uncertainty horizontal +/- 13.5 km (8.4 miles); depth fixed by location program
Parameters NST=350, Nph=351, Dmin=416.3 km, Rmss=1.46 sec, Gp= 29°,
M-type=centroid moment magnitude (Mw), Version=A
Source USGS NEIC (WDCS-D)
Event ID usc0001xgp
USGS source for all above info
Also, most important is the depth of the big quake itself. 32 km. Yes, those of you wondering, it DOES apply to us in the states. We are talking
about the same plate. The north American Plate. While the depth changes somewhat in areas, in general we see the quakes along the subducting zones at
about the same depth. Between 15 and 45 km or so (based on everything I have seen....if someone has more info, please share!!!)
Here are some supporting articles and info sites:
Article focusing on the subduction zone below vancouver
island
Great info mainly on Washignton and Oregon areas of subduction
That last article has a great map. Check it out:
Read the article. It's short. You clearly get the impression that all is NOT known and it is still all guess work as to where it is, how deep it
is, where it extends, etc.
There are too many quakes going on right now in Nevada for me to list them all, so I will just show you the 2.5+ ones for today:
MAP 2.8 2011/04/17 20:24:59 38.400 -118.739 0.0 NEVADA
MAP 3.0 2011/04/17 20:07:22 41.047 -123.362 34.5 NORTHERN CALIFORNIA
MAP 2.8 2011/04/17 04:18:05 38.394 -118.725 14.7 NEVADA
MAP 2.6 2011/04/17 03:59:59 38.362 -118.761 0.0 NEVADA
MAP 2.9 2011/04/17 02:44:02 38.389 -118.743 10.3 NEVADA
MAP 3.7 2011/04/17 01:19:26 38.401 -118.741 11.8 NEVADA
MAP 3.3 2011/04/17 01:05:03 38.392 -118.722 16.6 NEVADA
MAP 3.6 2011/04/17 00:57:50 38.362 -118.740 14.6 NEVADA
MAP 4.1 2011/04/17 00:55:46 38.369 -118.728 13.2 NEVADA
MAP 2.9 2011/04/17 00:50:41 38.383 -118.735 16.5 NEVADA
MAP 4.6 2011/04/17 00:45:37 38.394 -118.735 15.4 NEVADA
Source
The depth on the most recent one may change, since it just happened. Note the other depths though. I kept that one in Northern california in because
of where it was and its depth. The most recent, inlcuding the 4.1 and 4.6 are all around 15 km deep. That is getting towards the bottom of the North
American plate, I believe.