Chris

The Calaveras is very fast down by Hollister and then slows down as it moves north although not to an insignificant degree. Attached is link discussing study of northern Calaveras. It as 1861 NOT 1865 that it "supposedly" had big quake (my bad sorry). Apparently there is an ancient landslide covering the active trace, so no trench. There also is no evidence of a large quake in that area from 1861. Again I've read other papers that suggest the 1861 quake was no larger than 5.5. This site suggests it was 6.9. IF it were 6.9 I would have thought that there would have been major historical documentation in San Francisco like 1868 right? If a 6+ quake it may have been on the Calaveras cousin fault-Greenville about 15 miles east (but still in eastbay).

This is ONLY SPECULATION on my part, but seeing the Hayward quake occurred 1868 it makes me wonder if activity in this area of east bay is related to Hayward Fault. I.E. will magnitude 5s and 6s in this part of the east bay proceed by a few years the 7 that will hit the Hayward Fault.

• Paper on Northern Calaveras