[Geysers] Re: Earthquake swarm - question

[Gordon Bower]

The exact details of who can feel an earthquake depend on a whole lot of things other than the size of the earthquake and how far away it is (the type of ground the observer is standing on, and the orientation of the fault movement, are two major ones.) However:

As a rough rule of thumb, an alert sitting human will feel a magnitude 1 at 1km away, magnitude 3 at 10km away, and magnitude 5 at 100km away.

The most violent geyser-produced sounds (thumps from Giantess and Deep Blue) can exceed magnitude 0 but not by much. "Standard" Artemisia/Oblong thumps are much weaker, in the -1 to -2 range.

As far as bigger earthquakes... here in Alaska, my two largest earthquakes were a 6 about 100km away, which set my halogen lamp swaying alarmingly and made friends nervous, but didn't actually cause any damage, and the 7.9 of November 2002, which was Mercalli intensity VI (some people had bookcases tip over, I felt it in a moving car, and traffic signals flailed around like a hurricane was blowing) in Fairbanks, about 200km from the nearest portion of the fault.

GRB




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