Hi Lowell,

I'm not sure you if you're aware of the scientific earthquake averages for the SF Bay Area, but it has been a long held standard that the San Francisco Bay Area has a 3.0 at least once in every 18 days. It seems to me that it has changed since the Loma Prieta EQ in Oct 1989 in that there are fewer 3.0's.

The question then comes to mind, what physical area lies within the San Francisco Bay Area? Where I am in Sonoma County and my neighbor Napa County, we are in the "North Bay", so we are not included. So I would guess from Richmond to San Jose on the Hayward Fault, Bolinas to San Jose on the San Andreas and then from SF east to Concord and from Concord to San Jose on the Calavaras Fault. I hope this makes sense. You may need a map.

If you can determine a way to run a catalog(s) for this land mass from 1990 to present, thus excluding the majority of EQ's/aftershocks from Loma Prieta, we might have a much better idea of what the "current average" is and how it may have changed from past statistical averages. Or depending on the "correct" way to do this, does one run catalogs for the entire time period and then deduct the Oct 1989/Oct 1990 time period?

I can see now why math and cataloging would be a real fascination to someone who has a propensity to enjoying it. Just now I was thinking about Mammoth Lakes. If you excluded the 4 earthquakes that occurred in 1980 I wonder how often an EQ of 3.0 or greater occurs? It doesn't seem to be that frequent, but I think because of looking at maps all the time, its deceiving in what one choses to remember and what has actually happened.

Here's another good math thought aside from EQ's. I am putting in a new tile floor in my hallway and when I figured out how many tiles I needed it was easy because they are all 12 inches square. However, when you put them on the floor you can only fit in so many whole squares. I didn't think about that at the time and I bought a lot of extra's because it was the last of this pattern in the store. I knew I couldn't go back and get more if I was wrong. I figured I needed 51 squares. I haven't finished the project yet, but I have inserted 41 and the remainder will all be partial squares. So the question remains, will 10 cut up squares be enough? I won't know till I get there.

In my calculations I drew a floor plan of the subject area, but I forgot about placing the tiles so that the corners meet each other.I'll have to remember that in the future. I thought I'd share this story because there are a lot of people who do their own "how to" projects, a little reminder of this one might be helpful.

At some point in time the California EQ drought will be over. I can't help but wonder what will occur when that time arrives. Will it be like the late 1800's or early 1900's, or something totally different?

Petra