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Swarm of 200 earthquakes strike Yellowstone super volcano

File photo: Silex Spring in the Fountain Paint Pot area in Yellowstone National Park, Wyoming, June 21, 2011. (REUTERS/Jim Urquhart)

A swarm of more than 200 earthquakes hit Yellowstone National Park during the past two weeks, but that probably does not mean that the “big one” comes at this time, according to the geologists of the park.

The 200 temblors began on Feb. 8 and rising on Feb. 15 in an area of approximately 8 miles (13 kilometers) northeast of West Yellowstone, Montana, according to the u.s. Geological Survey (USGS). In reality, there are many more small earthquakes struck the region, but were simply too small for seismometers to pick them up, according to the USGS.

But while the swarm is larger than the daily seismic activity in the park, it is not a sign of a large earthquake, said Michael Poland, scientist-in-charge of the USGS Yellowstone Volcano Observatory in Vancouver, Washington.

A swarm of more than 200 earthquakes hit Yellowstone National Park during the past two weeks, but that probably does not mean that the “big one” comes at this time, according to the geologists of the park.

The 200 temblors began on Feb. 8 and rising on Feb. 15 in an area of approximately 8 miles (13 kilometers) northeast of West Yellowstone, Montana, according to the u.s. Geological Survey (USGS). In reality, there are many more small earthquakes struck the region, but were simply too small for seismometers to pick them up, according to the USGS.

But while the swarm is larger than the daily seismic activity in the park, it is not a sign of a large earthquake, said Michael Poland, scientist-in-charge of the USGS Yellowstone Volcano Observatory in Vancouver, Washington.

 

 

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“This is what Yellowstone has; this is Yellowstone is Yellowstone,” Poland told Live Science. “Experiences swarms all the time.”

In fact, the same area saw an even larger swarm between June and September 2017, when 2,400 temblors hit the same approximate region. The current swarm is in fact the continuation of the earlier swarm, Poland said. [Yellowstone, and Yosemite: Photographs of Two of the world’s Oldest National Parks]

Earthquake swarm

An earthquake swarm is usually defined as a higher-than-average number of earthquakes striking a region over a relatively short period of time, usually without a single major shock, according to the University of Utah Seismograph Stations, which measure seismic activity in the Yellowstone National Park. These swarms occur when the stress shift along the minor errors in an earthquake region, according to the USGS.

Swarms usually have two ultimate causes: the shift to large tectonic plates; or movement of water, gas or magma beneath the surface. If the abundance of hot springs and mud pools reveals, Yellowstone has plenty of liquid and gas just under the surface. Yellowstone is also in a region that is stretched and pulled apart, according to the USGS.

As a result, small earthquakes are the norm in Yellowstone, which is typically affected by the 1,000 to 3,000 earthquakes per year, according to the National Park Service. The largest earthquake on record was the magnitude-7.3 Hebgen Lake quake in 1959.

What does it mean?

So has the new earthquake swarm mean that Yellowstone is a greater risk for “the big one?” Probably not. Scientists still do not know exactly how to swarm the chances of major earthquakes, but a region’s seismic history can offer some clues, Poland said.

In this case, the area, which is near Norris Geyser Basin, is usually additional “swarmy,” he added.

“This particular area, in particular, is a hotbed of the swarm seismic activity, and it’s been a while,” Poland told Live Science. What’s more, the biggest shake recorded in this swarm came from magnitude 2.9, that is not particularly strong. In contrast, the swarm last summer had quakes as strong as magnitude 4.4, according to the USGS.

The new swarm is not quite business as usual, but it is in the neighborhood, he added. And it could be a reaction on decades-old seismic activity.

“One of the possible explanations for the reason why this area is so swarmy is that the whole crust in the area is still adjusting to the major earthquake in 1959,” Poland said.

Big one is possible

That said, there is a large earthquake is an undervalued risk in Yellowstone, Poland said. Apart from the 1959 earthquake with a magnitude-6.1 earthquake hit the Yellowstone region in 1975, according to the University of Utah Seismograph Stations.

“People tend to focus on the possibility of a huge eruption, which is vanishingly small,” but the magnitude-7 earthquakes could happen relatively more often, Poland said.

“When they happen, they are going to shake up the region pretty heavily, so people should be prepared,” Poland said.

If the Yellowstone supervolcano were to blow up, and if the eruption seemed to be the large that has taken place hundreds of thousands of years ago, the resulting far ash spewing could destroy the United States, Live Science reported earlier.

Originally published on Live Science.

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