Quakes Linked to Volcanic Activity

Saturday, October 13, 2007 04:32 AM

Seismologists with Natural Resources Canada say there have been more small earthquakes in a region southwest of Prince George . " We now have information that indicates there have been at least 50 earthquakes in that area over the past couple of days, although some were very small" says Seismologist and Research Scientist Garry Rogers.

( at left, the Nazko Cone, photo courtesy Natural Resources Canada)

The largest of the quakes to rumble through the Nazko region this week had a Richter magnitude of 3.2. That means, if anyone had been in the immediate area, ( 20 kilometers or so) they would have felt the shake, but even though scientists have contacted a lodge in the region, there have been no reports of humans "feeling" the quakes.

Rogers says they have been able to get a better indication of not only the exact location, but the depth of quakes as well. "We now know the quakes are happening about 25 kilometers below the surface of the earth so that rules out any hydro-thermal cause, and the area is not on a fault line, so we believe the quakes are related to volcanic activity."

The area is home to the "Nazko Cone" which is relatively young (7200 years old) that is part of a volcanic line that runs from west to east across B.C. "This would be considered a benign volcano" says Rogers. He says they believe the magma is moving at 25 kilometers below the surface but says there is no immediate concern "It would take a long time for it to move to the surface" but they will be monitoring the situation.

(at right, map shows in purple, the Anahim Volcano Belt, which is home to the Nazo cone. The borwn shaded areas indicate other volcanic belts which are either in B.C. or which could impact the province)

Next week, a satellite seismic link will be set directly on the surface directly above the quakes. "We will monitor to see if there is any sign of the quakes at lower depths, that would indicate the magma would be moving." Rogers says something like this has happened before, in Bella Coola. "In 1940 people kept reporting they were feeling quakes, but the seismic instruments were too far away to pick up the activity. That went on for 3 years before the activity stopped."

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