Hi Chris. I thought about that while doing the search. The earliest recorded quake was a 3.7Ml on 03/11/1943. This was outside the area that I used. The first 1.0+ quake recorded was in 1973 and it is inside the area I used.

I have a feeling there will be fewer quakes the further north one goes. This isn’t because there were fewer quakes, but more likely not felt, or recorded. This would be in the 40s maybe even the 50s depending on the size of the quakes. There were quakes smaller (just barely) then 4.0Ml+ in the 50s in the area I used so I’m fairly confident the count is good.

I kept the area purposely small because of the increase in population for the North Bay Area. The area of chief concern is the Rodgers Creek Fault from Santa Rosa south to San Pablo Bay and for the most part that area has a gap in the number of quakes recorded. There have been a couple of small swarms such as the one in Dec. of 1981, but for the most part quakes are far and few between.

The area I’m looking at is north of the quiet zone, but could be an indication of stress building towards a much larger quake, or could be nothing more then a on going cycle we haven’t seen before.

Given the nature of quakes I don’t think we should wait to see some good indications (what ever they may be) that were going to have a major quake to prepare for it. Take Care…Don in creepy town