Will Mount St Helens Erupt, Even As Small Earthquakes Shake It?

For the past two months, about 130 small earthquakes have been shaking the surface just below Mount St. Helens. Even though experts feel that it will erupt at any moment, information indicates that it is still alive.

Mount St. Helens is found in Washington state, 95 miles south of Seattle and approximately 55 miles northeast of Portland, Ore. The last time it erupted was on May 18, 1980.

The U.S. Geological Survey (USGS) says that currently, there are no anomalous gases or signs of the magma or molten rock undergoing inflation or transforming due to the tiny earthquakes here.

As there would not be an immediate eruption, the volcano is reported to be recharging. There might be an eruption in the future, even though it would not happen soon.

Every small earthquake measures a magnitude of 0.5 or less. The largest one is 1.3. They are situated 1.2 to four miles beneath the surface of the earth, so they would be difficult to feel even if someone were right above them on the surface.

The frequency of the earthquakes has been increasing since March 14, "reaching nearly 40 located earthquakes per week," according to the USGS.

Hence, scientists are paying attention to them. The magma collection here is "re-pressurizing", which is a process that can simmer quietly for years continuously, though the eruption would not take place. Many small earthquake swarms have been observed in 2013, 2014 and the 1990s.

The earthquakes seem to stem from a slip on a small fault.

"Such events are commonly seen in active hydrothermal and magmatic systems," the USGS said. "The magma chamber is likely imparting its own stresses on the crust around and above it, as the system slowly recharges. The stress drives fluids through cracks, producing the small quakes."