Don, I found your link about the Loma Prieta earthquake to be very informative. However, the Tables referred to in the article were not accessible. I really wanted to view Table 2, which was labelled "CALIFORNIA SEISMICITY, JANUARY 1980 THROUGH DECEMBER 1986, which would have shown the average numbers of earthquakes per year in California for different magnitudes. This would have answered my question that I posed here a few weeks ago.

So, this time I did a search and came up with the following from Cal Berkeley in their FAQ section -- seems that a 4th grader asked a similar question -- (hmm, I am humbled that my level of inquisitiveness is similar to a 4th grader's) -- nevertheless, I thought this was worth posting for those who have not seen these numbers before.

"As a function of magnitude, the number of events [in California] analyzed per year is:

Magnitude -------------Rate---------------
(eq/yr) (eq/mo) (eq/wk) (eq/day)

>= 1 29545 2462 568 81
>= 1.5 16038 1336 308 44

>= 2 6076 506 117 17
>= 2.5 1950 163 38 5.3

>= 3 604 50 12 1.7
>= 3.5 200 17 3.8 0.55

>= 4 65 5.4 1.3 0.18
>= 4.5 20 1.7 0.38 0.055

>= 5 6.8 0.57 0.13 0.019
>= 5.5 2.2 0.18 0.042 0.0060

>= 6 1.2 0.10 0.023 0.0033
>= 6.5 0.6 0.05 0.012 0.0016

...Note that the above table is not reliable at magnitudes above 6 because the 10 year seismicity sample is not sufficiently long to include a lot of magnitude 6+ earthquakes. In generating the above table, we assumed that the rate at which earthquakes occur does not vary with time. Large aftershock sequences violate this assumption."

I am unclear as to what time period this covers, but I believe it is 1970 through 1997. A link then provides histograms of annual seismicity for that same time period for all events and for events of varying magnitudes (2.0, 3.0, 4.0, 5.0)

Barbara

• HOW MANY EARTHQUAKES ARE RECORDED IN CALIFORNIA EVERY DAY, WEEK, AND MONTH?