Earthquake swarms are mysterious, but usually not threatening. Living in northern California, I've seen lots of them—I even have played with them. But the March-April swarm in the Reno area is unusual. First, it has lasted longer than typical swarms. Second, it hasn't yet reached a peak. Third, the events are quite shallow. Fourth, it has gotten a formal name, the 2008 Mogul-Somersett sequence. To follow daily developments, bookmark the University of Nevada Reno's special page for the west Reno swarm.
Nevada geologist Silver Fox, of the Looking for Detachment blog, is wondering whether the quake swarm is being triggered somehow.
Comments
Any chance this could be an unnamed blind thrust fault? The structural elements for blind thrust faults seem to be in place for this . .
The focal mechanisms aren’t compatible with a thrust, though. They’re strike-slip, all of them.