Wednesday, October 30, 2013

Yellowstone Volcano's Killer Hazard: Earthquakes


A supervolcano blasting Yellowstone National Park to smithereens may capture the imagination, but the region's real risk comes from earthquakes, researchers reported in Denver on Sunday (Oct. 27) at the Geological Society of America's annual meeting.
"The pervasive hazard in Yellowstone is earthquakes," said Robert Smith, a seismologist at the University of Utah. "They are the killer events."
Smith and his collaborators analyzed 4,520 earthquakes in and around Yellowstone that struck between 1985 and 2013. Their goal: Create the best picture ever of the magma chamber hidden beneath the park's colorful hot springs and spectacular geysers. A side benefit was a better view of the seismic risk from nearby faults.
One of these faults triggered the most destructive earthquake ever recorded in the Rocky Mountains — the deadly magnitude-7.3 Hebgen Lake quake in 1959. The epicenter was about 15 miles (24 kilometers) north of West Yellowstone.
Smith said the probability of another magnitude-7 or larger earthquake on one of the major faults near Yellowstone is 0.125 percent. The number reflects the chance an earthquake will occur in any given year, based on past records. Read More