Aug. 6, 2007 — Ambiguous, preliminary evidence indicates that a coal mine cave-in that trapped six miners early Monday in Utah generated seismic waves that were recorded as a magnitude-3.9 earthquake, according to the University of Utah Seismograph Stations.

There is no evidence that the earthquake triggered the mine collapse, says Walter Arabasz, director of the Seismograph Stations.

Some news media are reporting incorrectly that the quake triggered the mine collapse, apparently because the cave-in first was reported about an hour after the quake.

The magnitude of the quake was revised to 3.9, slightly smaller than the earlier estimate of 4.0, Arabasz says.

The quake at 2:48 a.m. MDT was centered near the Crandall Canyon coal mine, where six miners were trapped by the cave-in.

Arabasz said the seismic wave patterns from the quake appear consistent with the idea that the mine collapse was the source of seismic waves recorded as the earthquake.

There is a long history of earthquakes being generated by collapses in mines in Utah and elsewhere.