Yellowstone Supervolcano Earthquake Swarm Hits More Than 1,200 Events

Yellowstone National Park Geyser
A view of a hot spring at the Norris Geyser Basin at Yellowstone National Park on May 12, 2016. Scientists have recorded over 1,200 earthquakes in the last six weeks at the site. Mladen Antonov/AFP/Getty Images

Researchers have recorded more than 1,200 earthquakes at Yellowstone National Park, part of an ongoing earthquake swarm now in its sixth week.

Seismologists from the University of Utah have been monitoring the swarm since it first began on June 12, on the western edge of the national park. As of as of 9:45 a.m. Mountain Daylight Time (MDT) on Wednesday, the University of Utah Seismograph Stations (UUSS) had recorded 1,284 events, the largest being magnitude 4.4.

Despite the activity, experts believe the earthquakes are unlikely to cause a supervolcano eruption—an event often mistakenly believed to be catastrophic; the most likely scenario would be a lava flow with minimal direct effect outside the national park.

Almost 60 percent of the earthquakes recorded (764 events) were in the magnitude 0 range or lower, which is considered a small event that can only be recorded with sophisticated instruments used in earthquake monitoring.

Only seven events were in the magnitude 3 range, with one measuring 3.6 magnitude recorded on Tuesday. Another 105 earthquakes were in the magnitude 2 range, and 407 earthquakes in the magnitude 1 range, according to the university's latest report.

While increased seismic activity is usually a sign of volcanic eruption, Jamie Farrell, research professor at the university, told Newsweek in June that the ongoing event is unlikely to lead to an eruption as earthquake swarms are a common event in Yellowstone.

"When a volcano starts 'acting up' prior to an eruption, one of the typical signs is increased seismicity. However, it is usually just one of the signs of an impending eruption. Other signs include, large changes in surface deformation, changes to the hydrothermal system and changes in gas output. We monitor for all these things at Yellowstone," he said.

"Typically if we see just one of these things, it doesn't necessarily mean there is an eruption coming. If we start to see changes in all these things, then a red flag may be raised," he added.

While the current swarm is larger than the average recorded, it is by no means the largest, Farrell said. In October 1985, an earthquake swarm recorded in Yellowstone lasted for three months, recording more than 3,000 earthquakes. More recently, over 2,000 earthquakes were recorded in a swarm that lasted for about a month in January 2010.