Initial reports suggested that an earthquake triggered the Crandall Canyon coal mine collapse near Huntington, but further investigation indicated otherwise. Data collected on waves from the event appear similar to the motion produced from an implosion, said Relu Burlacu, manager of the University of Utah Seismograph Stations.

"It doesn't fit the model of an earthquake," he said, but stressed that this is not a definitive answer.

Mine officials have been reporting that an earthquake caused the mine collapse. Initial reports placed the cave-in an hour after the seismic event.

Robert Murray, CEO and president of Cleveland-based Murray Energy Corp., which owns the Emery County mine, said there were no operations that could have sparked the mine collapse.

Burlacu said if the collapse occurred an hour after the magnitude 3.9 event, then there was no data recorded from the cave-in.

Tony Lowry, a Utah State University geophysicist, said the first data recorded on the motion of a seismic event can tell a lot about the origins of the event. While he has not seen all the available data on the Monday event, more details could come to light in the coming days after further investigation.

"We are into a post-mortem phase," said Walter Arabasz, director of the seismograph stations.

The evidence now appears to point toward a collapse-type event, he said. But there is the possibility that a shallow earthquake near the mine could have occurred close to the time of the collapse.

Arabasz said researchers will need better information on exactly where the collapse occurred as well as a better time for the event, in addition to more seismological details, to put the puzzle together.

Regardless of the seismic event's origin, this coal mining area in Utah sits near active faults, where earthquakes happen.

Studies have shown that as mining takes place in seismically active areas, some activities can alter the stresses on faults, he said.

Scientists are not claiming that any particular activity sparked this event, but mining and drilling activity have been known to cause or hasten earthquakes in certain circumstances, he said.

Jim Evans, a USU geologist, said a key will be to better determine a more exact reading for the depth at which the earthquake took place. That information could help resolve some of the remaining questions surrounding the mine collapse.

glavine@sltrib.com