A swarm of 288 earthquakes in the Yellowstone National Park region last month has prompted yet another round of hype over the seismically active “supervolcano” resting below the surface of the park boundaries, yet experts are quick to caution that this is no cause for concern. Again.
“Yellowstone is one of the most seismically active areas in the United States. Approximately 700 to 3,000 earthquakes occur each year in the Yellowstone area; most are not felt,” writes the Yellowstone National Park Service. “They result from the extensive network of faults associated with the volcano and surrounding tectonic features.”
Three swarms of earthquakes – shockwaves that occur close together in time and location – occurred throughout the month of May. May 4 saw 12 events, May 22 another 39, and 100 events occurred on May 29, the largest of them being a “minor earthquake” of a magnitude 3.1 near Norris Junction, according to an update released by the United States Geological Survey. Like clockwork, the earthquake swarms around the park prompted concerns over the area’s “super-volcano,” a seismically active area featuring a caldera that stretches more than 2,800 meters (9,200 feet) through the State of Wyoming.
“Despite continuing rumors and fear-mongering media (unsupported by facts), there is currently no sign to believe that the so-called 'supervolcano' is about to erupt violently anytime soon,” notes the Volcano Discovery.
Yellowstone is one of the most seismically active regions in the US and is home to the most diverse collection of natural hydrothermal features in the world – including hot springs, geysers, mudpots, travertine terraces, and fumaroles – thanks in part to its unique volcanic and geological makeup located in the heart of the Rocky Mountains. (Some of them have even been known to “cough” up artifacts!)
Earthquake swarms like those seen in May help maintain this hydrothermal activity by keeping the “plumbing” system free and clear. Similar to other volcanoes around the world, earthquakes in the park are related to how volcanic fluids are transported “along the many small fractures in the shallow rocks over magma.” As stress from plate movement in the Earth’s crust lets off steam, so to speak, rocks along fault lines eventually slip or break from pent-up pressure. Energy is released in the form of seismic waves, or earthquakes, reverberating through surrounding rock.
The largest reported earthquake swarm occurred in 1985 with more than 3,000 quakes. Hundreds of earthquake swarms were also reported in 2009 and 2010.