Earthquake Swarm Could Be ‘Longest Ever Recorded’ at Yellowstone

Tourists walk beside Yellowstone Lake at the West Thumb Geyser Basin in the Yellowstone National Park, Wyoming on June 2, 2011. MARK RALSTON/AFP/Getty Images

The current earthquake swarm around the Yellowstone supervolcano is now the longest ever recorded, according to Newsweek.

The swarm started June 12, and over the past three or so months, around 2,500 earthquakes have been recorded so far—mostly in the western part of the national park.

The U.S. Geological Survey, in a monthly update on Oct. 2, said that 115 earthquakes were recorded at Yellowstone in September. Seventy-eight were part of the ongoing earthquake swarm 6 miles north of West Yellowstone, with the largest “earthquake” registering at 2.3-magnitude on the Richter scale.

“Including the events from the prior three monthly reports beginning on June 12, total swarm seismicity includes one earthquake of magnitude 4.4, 12 in the magnitude 3 range, and 185 earthquakes in the magnitude 2 range,” the USGS statement said.

Scientists have said that the swarm isn’t a signal of an impending supervolcano eruption.

“There are potentially several additional earthquakes visible on the webicorders that cannot be located because they are too small or overlap another event and are not included in these numbers,” the USGS said.

“No other swarm seismicity was observed in Yellowstone during the month of September,” the USGS said.

About 50 percent of the seismic activity recorded at Yellowstone comes in the form of earthquake swarms, the agency said. Swarms take place over several weeks or months with no clear pattern.

A scientist at the USGS told Newsweek said that it is “too soon” to tell if the swarm has ended.

“This is the sort of work that will happen in the months to come, as we gather up all of the available data and start crunching numbers,” Mike Poland says. “What we can say now is that through the end of September, the University of Utah has located 2,475 earthquakes in the swarm. This puts the 2017 swarm on par with that of 1985, which lasted three months and had over 3,000 located events.