This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Richard Wilson who specializes in Volcano seismicity and Armand Vervaeck. Please feel free to tell us about new or changed activity if we haven’t written about it. -
October 30 , 2012 volcano activity
Just saw this developing tonight beneath Mammoth Mountain volcano CA.
While these events are not uncommon at Mammoth, this episode is especially vigorous and is accompanied by appreciable deformation
(extension) across the volcano. Deep low-frequency events occur in the middle to lower crust and are believed to be caused by the transit
of magma or magmatic fluids upward beneath volcanoes. Such episodes at Mammoth may be followed (within days to weeks) by shallow
earthquake swarms.
Rodger
What is going on off the west coast of Canada on one of its islands
Nothing special – just a normal periodic subduction earthquake (although this one was a massive one)
How significant is the deformation that is occurring in the Postpile strain graph you’ve attached? Do you know?
Hi Justin, The dilatometers at Mammoth are very sensitive. I can quote the USGS explanation “can detect movement of less than an inch in 16,000 miles” but it doesn’t mean much to most of us. Needless to say, the instruments are detecting very slight expansion of the Mammoth Mountain edifice, nothing a human could perceive (and the swarm appears over. So nothing to be alarmed about.). I have witnessed strain steps in the dilatometer data before with these deep low-frequency swarms but they usually only affect the closest (Postpile) instrument. I note that all instruments show offset including those away from the volcano. I still believe we should watch for a shallow earthquake swarm in coming days. Cheers, Rodger
Hello Armand, I have not written in a while but there are some things no one else is talking about. First, the swarm off of Puerto Rico almost completely stopped when the swarm off the west scoast of Canada began. Then when the Canadian swarm slowed down the Puerto Rican nswarm picked up. Also i had some dialogue with the USGS about possible uplifting off of Puerto Rico but after some pleasant corresponding, I got no more response from them. I will try following up again to see if they have anything new. That’s all for now. Good luck. DR
We truly welcome these views, so please continue to monitor both phenomenons. From a rational tectonic view and taking into account the distances, a relation in between both look not acceptable, but …. We saw regular similar issues after a mega-earthquake in one plate boundary (for example the Pacific plate and their linked partial plates), but never related to big continental plates like the North American plate, although we know that the Caribbean area is a very complex plate environment. We are really interested in this subject. Please try to document what you have seen by grouping the number of quakes, their Magnitudes and the time frames. Armand
Hello, I got this site from my Brother, he said we need to watch this area! could be dangerous if it exploded? we live in Lake Don Pedro close to Sonora Ca. Let me know what you think! Jill
Jill, Area is not explosive. If.. if … if … eruptions would be merely lava flows (like you can see several of them in the area)