Scientists are closely monitoring a swarm of tremors hitting Yellowstone National Park over the past week.
At 11:32 a.m. Friday, a 3.5-magnitude earthquake was reported, followed by 3.2-magnitude quake at 12:40 p.m. and a 3.0 temblor at 1:15 p.m. And Friday’s quakes came on the heels of a series of tremors on Thursday.
No damage was reported, the Yellowstone Volcano Observatory said, and none was expected from quakes this small.
Still, professor Robert B. Smith, a geophysicist at the University of Utah and one of the leading experts on earthquake and volcanic activity at Yellowstone, said the swarm is of keen interest to scientists.
“Not business as usual”
“It’s not business as usual,” Smith said. “This is a large earthquake swarm, and we’ve recorded several hundred. We are paying careful attention. This is an important sequence.”
According to the Yellowstone Volcano Observatory, an “energetic earthquake swarm” began Dec. 27 beneath the northern part of the park’s Yellowstone Lake.
The largest of the quakes, according to the observatory, was a magnitude 3.9, registered at 10:15 p.m. Dec. 27.
More than 500 earthquakes have been recorded in this most recent string, the observatory reports.
The last major earthquake swarm was in 1985 and lasted three months, Smith said.
The observatory said similar swarms have occurred in the past without triggering steam explosions or volcanic activity.
However, the observatory said there is some potential for explosions and that earthquakes may continue and increase in intensity.
Monitoring on the minute
Joe Moore, director of the Wyoming Office of Homeland Security, said his office is tracking the events at Yellowstone on a minute-by-minute basis.
“It’s being followed very closely,” he said.
The Yellowstone Plateau is one of the largest super-volcanoes in the world and has gone through three volcanic cycles spanning 2 million years, which included some of the world’s largest-known eruptions.
The most devastating earthquake in the Yellowstone region in recent history occurred Aug. 17, 1959, when a 7.1-magnitude earthquake hit. It was centered near Heb gen Lake, Mont., killed 28 people and caused more than $11 million in damage. Geysers in Yellowstone National Park changed eruption times, and new ones began to erupt. On June 30, 1975, a 6.4-magnitude tremor hit the park.
Howard Pankratz: 303-954-1939 or hpankratz@denverpost.com
