Seismic Activity around Mt. Saint. Helens

[Dmonix Profile]

(news.yahoo.com) -- The United States Geological Survey is watching the Mount St. Helen's volcano closely after a series of earthquakes struck on Monday. The area around Mount St. Helen's in Washington state has been experiencing minor earthquakes since an initial quake measuring 4.3 in magnitude struck around 10:35 a.m. local time, according to the USGS. Since that first quake, several smaller aftershocks were registered ranging between 1.0 and 2.8 in magnitude.

All of these earthquakes were centered in an area approximately five to six miles north of the Mount St. Helen's crater near the Johnston Ridge Observatory. The quakes were registered at depths between 1.7 and 3.7 miles. In total, at least 12 small earthquakes were registered in the area since the first quake on Monday.

This series of small earthquakes occurring in approximately the same location over a short period of time is known as an earthquake swarm. According to the Global Volcanic Earthquake Swarm Database earthquake swarms are especially common around volcanoes and are often reliable methods of predicting an eruption but the Alaska Volcano Observatory website offered that there may be no need for alarm. The AVO website explained that while earthquake swarms may offer information that a volcano is becoming restless, they are not necessarily indicators of a pending eruption. According to the AVO, "Most seismic swarms are not precursors to eruptions."

The AVO website states that a great deal of seismic data from satellite imagery, deformation, gas measurements and the history of the volcano's geologic past are all taken into consideration when determining an eruption risk.

According to the USGS, seismic activity is common around volcanoes as volcanoes can produce various types of earthquakes--tectonic-type or volcanic-type. Tectonic-type earthquakes around a volcano occur when rocks break along faults or fractures around the volcano. Seismologists must determine if an earthquake near a volcano is tectonic or volcanic as the differences are very subtle.

More on the story here: http://news.yahoo.com/s/ac/20110216/sc_ac/7864744_usgs_watching_mount_st_helens_volcano_following_earthquake_swarm

After I've been saying for the last few months, that locally (Vancouver, British Columbia - The Lower Mainland) is quite blind to the fact of the "Big One" happening, because we so rarely feel any quakes to remind us. These small quakes were only about 3.0 at the most, though quite "shallow" which is why the had been fault by some locally.
I think I got to make sure my Quake kits all up to par hehe