What, Me Worry? 400 Earthquakes in One Week at Yellowstone Supervolcano

How was your week last week? Hot enough for you? Did you get caught in the rain? Whatever your weather scenario was, it can't top the week had by the supervolcano beneath Yellowstone National Park. After a long period of relative calm, the area around the volcano registered more than 400 earthquakes in a single week.

Most of the quakes were less than 1 on the Richter scale, too small to be felt. But the most powerful was a magnitude 4.5 quake on June 15th centered eight miles NNE of the town of West Yellowstone.

By Monday June 19, 464 earthquakes had been recorded inside the park. "This is the highest number of earthquakes at Yellowstone within a single week in the past five years, but fewer than weekly counts during similar earthquakes swarms in 2002, 2004, 2008 and 2010," said one seismologist. 

I for one had no idea they came in swarms. It's safe to say you'd rather face a swarm of just about anything else.

Seismic activity at a volcano can signal that an eruption is about to take place. However, geologists are never sure exactly when a volcano will erupt. While the chances are low -- about 1 in 730,000 -- geologists have predicted what would happen in the event of an eruption at Yellowstone. For one thing, it wouldn't stay at Yellowstone -- the entire country would be covered in a blanket of ash about a meter deep. This is one volcano we do not want to make angry.  

The Yellowstone caldera has not erupted for 70,000 years. So maybe it is due.

Experts say that an eruption would not likely be the intense scenario that was modeled in the study.

"Besides intense earthquake swarms (with many earthquakes above M4 or M5), we expect rapid and notable uplift around the caldera (possibly tens of inches per year). Finally, rising magma will cause explosions from the boiling-temperature geothermal reservoirs. Even with explosions, earthquakes and notable ground uplift, the most likely volcanic eruptions would be the type that would have minimal effect outside the park itself."