HELENA (AP)
A small earthquake shook the Grass Range area, but there were no immediate reports of injuries or damage. The quake struck at 11:27 p.m. Sunday and registered a magnitudeCentral Montana are relatively infrequent," he said. "To have an earthquake this large come along is somewhat surprising, but not unprecedented. "I think this shows that nowhere in the state is completely exempt from the possibility of an earthquake." Earthquakes in Montana usually happen in the western part of the state, where most of the tectonic movement occurs. Stickney said Montana averages five temblors a day, but most are smaller than a magnitude 2.0.4. 1, according to Mike Stickney with the Earthquake Studies Office at the Montana Bureau of Mines and Geology. The U.S. Geological Survey recorded the quake at a magnitude 3.5. "It's not that unusual to get some variations between magnitudes from different agencies," Stickney said. He attributed the discrepancy to the use of different scales and seismic stations and added the two offices would get together and rectify the difference in the next week or so. The epicenter was about 8 miles south-southwest of Grass Range, Stickney said, adding he received no reports from anyone who had felt the temblor. He characterized it as a "light" earthquake, saying it was "noticeable but not damaging." Aftershocks were possible but none had been recorded as of Monday afternoon, he said. The earthquake was interesting because it happened in an area "with pretty low levels of previous seismicity," Stickney said. "Earthquakes out on the plains in
