YELLOWSTONE — According to the U.S. Geological Survey (USGS), over 90 earthquakes have occurred in a cluster southwest of Yellowstone Lake within 24 hours.
Relax, it’s not the end of the world. Earthquakes are quite common in Yellowstone. The National Park Service says that approximately 700 to 3,000 earthquakes occur each year in the Yellowstone area. Furthermore, they were relatively small quakes. Only seven rose above 2.5 magnitude, and none topped 3. Damage does not usually occur until the earthquake magnitude reaches somewhere above 4 or 5, according to the USGS.
The park service says that Yellowstone commonly experiences “earthquake swarms”—a series of earthquakes over a short period of time in a localized area. The largest swarm occurred in 1985, with more than 3,000 earthquakes recorded during three months on the northwest side of the park.
Hundreds of quakes were recorded during swarms in 2009 near Lake Village and 2010 between Old Faithful area and West Yellowstone. Scientists posit these swarms are due to shifting and changing pressures in the Earth’s crust that are caused by the migration of hydrothermal fluids, a natural occurrence of volcanoes.
In Yellowstone, earthquakes actually help to maintain hydrothermal activity by keeping the “plumbing” system open. Without periodic disturbance from relatively small earthquakes, the small fractures and conduits that supply hot water to geysers and hot springs might be sealed by mineral deposition. Some earthquakes generate changes in Yellowstone’s hydrothermal systems.
What made this event stick out was the number of earthquakes in the same cluster, within a short period of time. This is an abnormal event, but certainly not unheard of.
The USGS says that the chances of Yellowstone erupting are 1 in 730,000 or 0.00014%. Even if it were to erupt, most scientists think that the buildup preceding a catastrophic eruption would be detectable for weeks and perhaps months to years.