Over 40 earthquakes shake Jackson Hole, Wyoming
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Pastor Dale Morgan
Aug 6, 2010, 6:14:10 AM8/6/10
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Great Earthquakes In Diverse Places
Over 40 earthquakes shake Jackson Hole, Wyoming
By Cory Hatch, Jackson Hole, Wyo.
August 6, 2010
Roughly 40 earthquakes have rumbled across Jackson Hole from their epicenter in the Gros Ventre Mountains since the first shook the region Wednesday evening.
Scientists with the U.S. Geological Survey recorded at least four earthquakes greater than magnitude 3.0, and as of Thursday afternoon, 588 people in 36 ZIP codes reported feeling the earthquakes at the Earthquake.usgs.gov “Did you feel it?” website.
The largest quake, which shook Jackson at 6:04 p.m. Wednesday, was preceded by a small foreshock a few seconds earlier, said University of Utah geophysicist Bob Smith. Researchers say that earthquake was a magnitude 5.0 or greater, which is considered a moderate quake. Most of the 40 or so that followed were magnitude 1 or 2.
Smith said the 40 earthquakes are not considered a swarm, like the earthquake swarms of hundreds of small quakes that sometimes shake Yellowstone National Park. He called these a sequence.
“This area of Jackson Hole has had persistent seismicity for decades,” he said.
Smith said the fault lines in the area are quite old, dating back 60 million to 80 million years, and are the result of stress related to movement in the Basin Range area, not the Teton Fault.
“As we get into this area, there’s not big normal faults,” he said. “My speculation is that the crust is highly fractured in the area. There are probably pre-existing fractures in the area that are being overloaded by the activity.”
The recent activity mirrors almost exactly a magnitude 4.8 quake at the same location that occurred in Jan. 7, 2004, said Harley Benz, scientist in charge of the USGS National Earthquake Information Center.
“The style of faulting is identical,” he said, adding that earthquakes in the Gros Ventres are not uncommon.
The earthquake likely occurred eight to nine kilometers (about five miles) beneath the surface of the earth, Benz said.
At the Red Rock Ranch, in the Gros Ventre area near the epicenter of the quake, “we had stuff falling off shelves,” said Addie Hare, ranch co-manager. “Wine glasses and bottles were falling and breaking. Pictures were falling off the walls. Our bar area was a mess.”
“It was loud,” Hare said. “It was a definite rumbling that got louder as it got closer. The whole building shook. There were dust plumes from where rocks had rolled off mountains surrounding us.”
The quake even spooked some of the ranch animals.
“The horses were running differently, and my dog was definitely spooked,” Hare said. “She did not want to leave my side.”
About 9 a.m. Thursday morning, Hare reported feeling another temblor as she hiked west of the Crystal Valley.
“Within two seconds we heard crashing boulders either falling behind us or the other side of the valley,” she said.
In Jackson, Victor, Idaho, resident DayDay Montesclaros felt two of the earthquakes, one Wednesday evening and one Thursday morning.
“I was pumping gas [about 6 p.m. Wednesday night], and the earth started to move,” she said. “I saw the pump shake, then I turned ... and my car was shaking.”
The following morning, Montesclaros felt another earthquake at her desk at Snow King Resort.
“It didn’t feel as bad as the first,” she said.
While the earthquakes don’t pose an immediate threat, it’s a good reminder to area residents, Benz said.
“Any moderate earthquake has a very small probability of being a foreshock to a larger one,” he said. “If you just look at the Tetons, they were formed by large earthquakes. [You] are living in the seismically active western U.S.”
Smith called the event a “wake-up call.”
“I think what people need to recognize is that Jackson Hole is earthquake country,” Smith said. “We need to be prepared.”
“One of these days, we’re going to have one on the Teton Fault ... [that] is going to be thousands of times larger,” he said.
Teton County Emergency Management reported no serious damage or injuries from the quake.
“Most of the calls into the dispatch center were from people who just wanted to know, ‘Was that an earthquake?’ Teton County Sheriff’s Office communication center manager Alyssa Watkins said in a statement.
The best thing people can do is be prepared, said Rich Ochs, interim emergency management coordinator. In a statement, Ochs suggested putting together a 72-hour kit that contains survival supplies for a person and his or her family to last at least three days. Ochs also recommended that people formulate their own family disaster plan and be informed about the types of disasters that can affect Teton County.
Over 40 earthquakes shake Jackson Hole, Wyoming
By Cory Hatch, Jackson Hole, Wyo.
August 6, 2010
Roughly 40 earthquakes have rumbled across Jackson Hole from their epicenter in the Gros Ventre Mountains since the first shook the region Wednesday evening.
Scientists with the U.S. Geological Survey recorded at least four earthquakes greater than magnitude 3.0, and as of Thursday afternoon, 588 people in 36 ZIP codes reported feeling the earthquakes at the Earthquake.usgs.gov “Did you feel it?” website.
The largest quake, which shook Jackson at 6:04 p.m. Wednesday, was preceded by a small foreshock a few seconds earlier, said University of Utah geophysicist Bob Smith. Researchers say that earthquake was a magnitude 5.0 or greater, which is considered a moderate quake. Most of the 40 or so that followed were magnitude 1 or 2.
Smith said the 40 earthquakes are not considered a swarm, like the earthquake swarms of hundreds of small quakes that sometimes shake Yellowstone National Park. He called these a sequence.
“This area of Jackson Hole has had persistent seismicity for decades,” he said.
Smith said the fault lines in the area are quite old, dating back 60 million to 80 million years, and are the result of stress related to movement in the Basin Range area, not the Teton Fault.
“As we get into this area, there’s not big normal faults,” he said. “My speculation is that the crust is highly fractured in the area. There are probably pre-existing fractures in the area that are being overloaded by the activity.”
The recent activity mirrors almost exactly a magnitude 4.8 quake at the same location that occurred in Jan. 7, 2004, said Harley Benz, scientist in charge of the USGS National Earthquake Information Center.
“The style of faulting is identical,” he said, adding that earthquakes in the Gros Ventres are not uncommon.
The earthquake likely occurred eight to nine kilometers (about five miles) beneath the surface of the earth, Benz said.
At the Red Rock Ranch, in the Gros Ventre area near the epicenter of the quake, “we had stuff falling off shelves,” said Addie Hare, ranch co-manager. “Wine glasses and bottles were falling and breaking. Pictures were falling off the walls. Our bar area was a mess.”
“It was loud,” Hare said. “It was a definite rumbling that got louder as it got closer. The whole building shook. There were dust plumes from where rocks had rolled off mountains surrounding us.”
The quake even spooked some of the ranch animals.
“The horses were running differently, and my dog was definitely spooked,” Hare said. “She did not want to leave my side.”
About 9 a.m. Thursday morning, Hare reported feeling another temblor as she hiked west of the Crystal Valley.
“Within two seconds we heard crashing boulders either falling behind us or the other side of the valley,” she said.
In Jackson, Victor, Idaho, resident DayDay Montesclaros felt two of the earthquakes, one Wednesday evening and one Thursday morning.
“I was pumping gas [about 6 p.m. Wednesday night], and the earth started to move,” she said. “I saw the pump shake, then I turned ... and my car was shaking.”
The following morning, Montesclaros felt another earthquake at her desk at Snow King Resort.
“It didn’t feel as bad as the first,” she said.
While the earthquakes don’t pose an immediate threat, it’s a good reminder to area residents, Benz said.
“Any moderate earthquake has a very small probability of being a foreshock to a larger one,” he said. “If you just look at the Tetons, they were formed by large earthquakes. [You] are living in the seismically active western U.S.”
Smith called the event a “wake-up call.”
“I think what people need to recognize is that Jackson Hole is earthquake country,” Smith said. “We need to be prepared.”
“One of these days, we’re going to have one on the Teton Fault ... [that] is going to be thousands of times larger,” he said.
Teton County Emergency Management reported no serious damage or injuries from the quake.
“Most of the calls into the dispatch center were from people who just wanted to know, ‘Was that an earthquake?’ Teton County Sheriff’s Office communication center manager Alyssa Watkins said in a statement.
The best thing people can do is be prepared, said Rich Ochs, interim emergency management coordinator. In a statement, Ochs suggested putting together a 72-hour kit that contains survival supplies for a person and his or her family to last at least three days. Ochs also recommended that people formulate their own family disaster plan and be informed about the types of disasters that can affect Teton County.
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