Volcanic hotspot Yellowstone was shaken by 81 earthquakes in February across the US national park, as detected by University of Utah Seismograph Stations. The United States Geological Survey (USGS) said earthquakes of different sizes were reported across the region. The largest one was magnitude 3.1, located 14 miles south of Montana on February 16 at 2.22pm local time. The strongest earthquake of the swarm of 17 measured magnitude 1.7 and was located five miles north of Montana.
USGS said the seismic activity was nothing to worry about, saying: “Earthquake swarms like this are common and account for roughly 50% of the total seismicity in the Yellowstone region.
How overdue is Yellowstone for an eruption? Is caldera active?
A Yellowstone eruption would kill thousands of people and destroy entire cities, even disrupting entire continents.
When Yellowstone last erupted 630,000 years ago, the supervolcano spewed 240 cubic miles of ash and rock into the air.
Recent activity has seen the caldera – the cauldron-like crater that forms following a major volcanic eruption – sinking, continuing to the present time.
But while Yellowstone National Park says the subsidence correlates with earthquake activity, it does not mean an eruption is imminent.
The park says Yellowstone will “probably” erupt again but not for at least thousands of years.
An eruption is impossible to stop and beyond the control of human ability.
However, the type of activity most commonly expected would be lava flows.
USGS says there have been no “significant changes” in Yellowstone surface deformation recently.
In its latest update on March 1, the scientific agency wrote: “Ground subsidence of Yellowstone caldera continues, as it has since 2015, at a rate of a few millimeters per month.
“In the area of Norris Geyser Basin, GPS data indicate no vertical deformation (the area has shown little net change since October 2018).”
The volcano’s alert level is currently set at normal.
The park, which celebrated its 147th birthday on March 1, said there were four water eruptions of Steamboat Geyser last month on February 1, 8, 16, and 26.
Steamboat is the world’s tallest active geyser, with eruption levels shooting up to 300ft high.
USGS said: “Discharge measured at the Tantalus stream gage suggests that these eruptions may have been smaller than past events of the current sequence (which started in March 2018), although it is difficult to confirm this without direct observations.”