A minor earthquake in the Star Valley last week has geologists wondering whether a larger earthquake might be in store for the area.
The Wyoming State Geological Survey in Laramie announced in a news release Wednesday that an earthquake with an estimated magnitude of 3.2 to 3.6 occurred near Bedford on Saturday.Jim Case, head of the survey's Geologic Hazards Section, said his office is not sure whether the seismic activity may be a precursor to more powerful earthquakes in the Star Valley Fault system.
"This may be an isolated event, but we have so many questions on this that we just don't know," he said. "Anything that occurs in the near vicinity of a major fault system . . . then we feel it is prudent to put out a press release."
Information from the National Earthquake Center and University of Utah indicated the earthquake's epicenter could have been located within 1.5 miles of the Star Valley Fault, which is capable of generating an earthquake with a magnitude of 7.3 to 7.5, Case said.
Case said his office had difficulty tracking down information on the earthquake because of the federal government shutdown that limited activity in the National Earthquake Center and because of a lack of seismic stations in Star Valley.
The earthquake itself caused no damage, said Chuck Young, Lincoln County's emergency management administrator.
The Star Valley Fault, which runs along the east side of the Star Valley, is just as significant a fault as the Teton Fault, Case said. Experts have long been concerned that a major shift in the Teton Fault could destroy Jackson and the Jackson Lake Dam.
Studies indicate that the Star Valley Fault becomes active every 2,500 to 6,000 years and that the last time it was active was 5,500 years ago.
"It is near the time statistically when you would start to wonder if it would start to activate again," Case said. "We're either well beyond (the activation time) or getting close. Of course, getting close in this case is 500 years."
The last major earthquake in the area, in February 1994, was actually centered in Idaho on a fault system separate from the Star Valley Fault.
The earthquake, with a magnitude of 5.9, was preceded by several smaller earthquakes, Case said.
"But there was no way to know until after the fact," he said.