Posted by Lowell on February 22, 2002 at 13:43:46:
History has a way of repeating itself if conditions are appropriate. Back in October of last year there was a Mb 5.1 earthquake near Anza, CA. That event occurred at nearly exactly midnight solar time in association with a flare. I am attaching the post to this board regarding that coincidence. Also, Petra had suggested (in jest) yesterday that my appearance back on this board and the sudden increase in solar activity might be more than coincidence. In an interesting coincidence, the last moderate event in California occurred on Dec 8 as a Mb 5.2 in the general Calexico region, four days before my last post to this board; and today's occurred in the same general area as a Mb 5.4 5 days after my return to this board. Coincidences do happen. Note on relation between Anza earthquake and solar flare - post # 13223 in archives "Given recent discussions on this board regarding the effect of CME, geomagnetic effects and flares on seismicity, I thought someone might notice this. But since no one else has posted this observation yet, I think I will get the first crack after all. The Anza earthquake occurred at 11:56 p.m. PST, which is nearly exactly midnight there by sun-time. As pointed out many times recently when a flare occurs the areas most affected are at sub-solar and anti-solar latitudes - that is where it is local sun-noon and local sun-midnight. So was there a flare that may have triggered the Anza earthquake. Indeed there was and it was reaching it's maximum just as the Anza earthquake occurred. The flare had started about 20 minutes earlier and reached maximum output at 12:09 a.m. PST. The flare had the following parameters:
Flare # START MAX END CLASS 9180 + 0734 0809 0819 M3.2 Flare #9180 was the second largest in more than a week, the last large flares occurred on October 28 - M3.6 and Oct 22 (M6.5). About an hour after flare 9180 several significant earthquakes occurred including the Ms 7.0 in New Britain and the Anza earthquake in southern California. The Anza event occurred at 07:54 UT near the maxima of flare #9180 and occurred while the epicenter was exactly anti-solar. It is likely that this flare was responsible at least in part for the timing of this rupture. For general space weather conditions see: http://sec.noaa.gov/today.html For Solar flare data see: http://sec.noaa.gov/ftpdir/indices/events/20011031events.txt"
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