As a series of earthquakes continued around Mt. St. Helens,
central California was struck by a 6.0 quake along the San
Andreas Fault, centered near Paso Robles. In recent days,
the West Coast has experienced an exceptional amount of
earthquake activity, with a cluster of quakes near Mammoth
Lake, the continuing disturbance around Mt. St. Helens, and
now this new quake. There is no evidence that the quakes are
related. It is believed by experts that the Mt. St.
Helens quakes may indicate magma movement within the
volcano, although increased carbon dioxide emissions have
not been observed at this time.
The quakes are centered about half a mile beneath the
surface of a large lava dome in Mount St. Helens' crater.
They are of the type that indicates the presence of
pressurized fluids or magma. Experts do not expect a large
explosion at this time, but the activity is unusual enough
to cause concern.
In the Mammoth Lake area, microquakes measuring one to two
on the Richter Scale have been continuing for a week. As of
5PM PDT on September 28, there had been twenty such quakes
in the past 24 hours. Since they began on September 18,
there have been hundreds.
The cause of these quakes is not known. There have been
earthquake clusters in the area before, one as recent as
1980, but not nearly the numbers and duration of this cluster.
Since earthquake prediction isn't perfected yet, we'll just
have to
trust
our vibes.
