Daily Archives: April 7, 2012


In a comment on the last post, it was mentioned that the frequency of earthquakes of any given magnitude or greater will be given by the Gutenberg-Richter law. It states that the expected number of earthquakes in a given region over a given span of time, of a given earthquake magnitude or greater, will be

N = 10^{a-bM},

where M is the quake magnitude, a and b are constants, and N is the expected number. For active regions, the constant b usually has a value near 1.

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Open Thread

For topics not related to other posts.

Deja Vu

A new study by scientists from the U.S. Geological Survey, not yet published but scheduled to be presented at the upcoming annual meeting of the Seismological Society of America, reports a dramatic increase in earthquakes of magnitude 3.0 or greater over a large area of the U.S. More interestingly, the report states that the increase is “almost certainly man-made,” and attributes it to oil and gas production.

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