Mount St. Helens' Recent Earthquakes Are Nothing To Fear

Small earthquakes that have recently taken place near Mouth St. Helens, a volcano that erupted in 1980 and caused a few dozen deaths, have stirred up concern among those who worry another eruption may happen in the near future. Put those fears to rest, folks — there's nothing to worry about. Researchers say there is no sign the volcano will blow anytime soon, and that so-called 'earthquake swarms' have happened in the recent past.

Starting around the middle of March, more than 130 earthquakes have been registered by the Pacific Northwest Seismic Network, with 20 of those happening in the last week. They're all small in nature, though, with the most powerful of them all topping out with a magnitude of 1.2. These are known as earthquake swarms, and they're nothing new in the area.

According to the U.S. Geological Society, the region saw similar earthquake swarms in 2013 and 2014, and they're getting smaller rather than bigger. The earthquake swarms that happened in the 1990s, for example, were more powerful and happened more frequently. What's causing the swarms?

Such swarms represent the volcano recharging itself with new magma, making up for what it lost during its 80s eruption. The new magma is moving up into the volcano's chamber, and small earthquakes happen when it does. A new impending eruption would have more signs than just small quake swarms, though, and at this point at least, the USGS hasn't found any of those.

SOURCE: Discovery