Scientists have warned that the Supervolcano in Yellowstone may be about to erupt after a record number of small earthquakes were recorded in the last three months.
An ongoing swarm of 25000 earthquakes since June 12 represents the longest ever in U.S. history, according to Newsweek.
Stuff.co.nz reports: US Geological Survey experts said it was “fascinating” to monitor the swarm and were eager to learn more about it, Newsweek said.
A total of 115 quakes were reported in the park in September according to a monthly update about activity at Yellowstone. Of those, 78 were part of the swarm in the north west of Yellowstone. The highest magnitude quake was 2.3 in September.
“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 statement said.
About half of the seismic activity at Yellowstone was part of the earthquake swarm, which occurred when many quakes took place over weeks or months with no clear sequence, unlike traditional earthquakes where there is a main event followed by a series of aftershocks.
USGS Yellowstone Volcano Observatory head scientist Mike Poland told Newsweek it was a “bit too soon” to say whether the swarm has ended.
“But the activity has certainly waned drastically since August, and the swarm appears to be winding down, if not completely over. It will probably take a little while longer to declare it ‘over’.”
The actual number of earthquakes is difficult to ascertain because quakes can overlap or are too small to be recorded, he said.
However, there are ways to retrospectively locate some of these events, so it could be that there have been “many times more earthquakes” than initially reported.
“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,” Poland said.
“What we can say now is that through the end of September, the University of Utah has located 2475 earthquakes in the swarm. This puts the 2017 swarm on par with that of 1985, which lasted three months and had over 3000 located events.
“[This is] certainly a fascinating event and one that we hope to learn more about through some post-swarm analysis. There’s a lot to work on this winter, for sure.”