I've Got It!
Posted by Petra Challus on October 26, 2000 at 22:50:37:

Hi All,

A friend of mine in seismology in Utah tells me these quakes are a result of mining operations in the area. The seismic networks are set a little to fine and thus these mining incidents are being related as quakes. He says there will be some changes soon and then they won't pick up these events in the future.

From North of The Golden Gate...Petra Challus