Yellowstone Earthquakes Under Supervolcano Caldera

A swarm of small earthquakes in Yellowstone National Park is the most intense measured there in years, leaving scientists puzzled.

The region is known for such swarms — 1,000 to 2,000 quakes occur annually in the park. Yellowstone's 10,000 geysers and hot springs, including the Old Faithful Geyser, may be the result of this geologic activity.

But the latest shaking is notable for the number of tiny temblors and their intensity, according to a statement yesterday from the University of Utah, where scientists monitor seismic activity in Yellowstone. (Yellowstone is located mostly in the northwest corner of Wyoming.)...

...Researchers have long predicted that the Yellowstone supervolcano will eventually erupt again, with devastating consequences for much of the United States. Half the country could be covered in ash up to 3 feet (1 meter) deep, one study predicts. But those same researchers say nothing suggests such an eruption is imminent. They point out, however, that Yellowstone seems to blow its top about every 600,000 years.

Meanwhile, the region's deep secrets are still being revealed.

Last year researchers reported on unusual slow movement below the surface that's tied to a newfound gradual sinking of the nearby Teton Range. And in 2006, scientists discovered that in the previous decade, the volcano had risen nearly 5 inches.

"Could it develop into a bigger fault or something related to hydrothermal activity?" wonders Robert Smith, a professor of geophysics at the University of Utah. "We don't know," he said this week.... ◼ http://www.livescience.com/ Yellowstone Earthquake Swarm Puzzles Scientists

US News & World Report ◼ The University of Utah Seismograph Stations reports that a notable swarm of earthquakes has been underway since December 26 beneath Yellowstone Lake in Yellowstone National Park, three to six miles south-southeast of Fishing Bridge, Wyoming. This energetic sequence of events was most intense on December 27, when the largest number of events of magnitude 3 and larger occurred....
◼ The earthquake center at the University of Utah
◼ March of 06 Uplift at Yellowstone Caldera (image source)
◼ News from the Yellowstone Caldera: Earthquakes
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◼ Part 2
◼ Part 3
◼ Part 4
◼ part 5
◼ Part 6

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◼ Earthquake Swarms in Yellowstone
"We've had larger swarms in the past, larger earthquakes, but the fact this is in Yellowstone Lake and it's releasing a lot of energy is very interesting to us," said Hank Heasler, park geologist.

The recent earthquake swarm caused no property damage to the nation's first park, but scientists said it could have altered some of the thousands of thermal features the park is famous for."...

...The recent earthquakes caused an eruption of volcanic dooms-day sayers to take to the internet. "We don't see any evidence of volcanic activity associated with this earthquake swarm."

The Yellowstone Volcano Observatory is a group of scientists, including Heasler, charged with keeping an eye on the situation. "Technology has improved greatly for the earthquake monitoring, satellite sensing of volcanic activity and we just do not see any of those indicators currently in Yellowstone," said Heasler.

The YVO streams live seismographs on its website. Heasler said this scientific data can be misinterpreted. For example, many people confused constant small pulses on a January seismograph as harmonic tremors, which are indicative of a pending volcanic eruption....