Posted by Don In Hollister on November 17, 2001 at 00:50:37:
Hi All. After doing a little digging into the 3.1 quake at Aptos I found that for the most part the quakes in that area have returned to the background level, which was in September of 1991 of which there have only been 7 within a 16Km radius of Loma Prieta epicenter. In some ways it is below the background level, which may be the results of a decrease in strain. When I opened it to 32Km I picked up a lot of quakes in the area of the Calaveras fault. I’m using the NEIC catalog, which doesn’t list any quakes below 2.0. The quake was 2.22Km NW of the Loma Prieta quake and was near the depth of the majority of the aftershocks. There were a total of 153 aftershocks within a 16Km radius of which 113 were at, or north of the epicenter. I cannot rule out that this may be an aftershock. However this is the first quake in this area in 3 years so there is a strong probability that it isn’t. Nor can I say with any degree of assuredly that it is a foreshock nor can I say that it isn’t a foreshock. In some ways I find it a little odd that there have been no aftershocks to this quake. Sort of reminds me of the Bolinas quake. There were no aftershocks to that one and there weren’t any foreshocks to it either. What it boils down to is that we had a 3.1 quake near Aptos. As to what it means is anybody’s guess. Take Care…Don in creepy town
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