Sunday, January 04, 2009

Yellowstone Quake Swarm Update 10

There really isn't news to report about the series of earthquakes that had been occurring at Yellowstone Park for the last week.  The news is really that after over 500 earthquakes in a very small area over the course of six-plus days, there have been none since yesterday just after midnight (approaching two days ago, actually). 

A very quiet earthquake list for the Yellowstone Lake area


Dr. Robert B. Smith, Research Professor of Geology & Geophysics at the University of Utah, and Director of the Yellowstone Volcano Observatory  Dr. Robert Smith bio

I'll be looking for interpretation from Dr. Smith and the team that has been studying the Yellowstone volcano system for many years, because even to them this was a unique event.  To me it felt very much like the magma chamber beneath Lake Yellowstone had either swollen or broken through a barrier and was moving to the Northeast during this period.  The webcorder movements were really hectic and seemed to show almost constant vibration in the area - and contrary to some web posters beliefs, this could not be accounted for by wind or other phenomena as the sensors are buried in specially designed borings several hundred feet down.  Even Katrina couldn't tweak those gauges!  Almost as suddenly as it had started, the swarm stopped, as if the moving magma had finally come up against a barrier that it didn't break through or move around.  Fortunately, this movement seems to have been achieved without creating a steam vent - which would likely have triggered at the least a geothermal explosion and at worst a supervolcanic eruption. 

The most fascinating thing about this was that it was clearly an event which was unprecedented - not in history, but in the recorded experience of human beings.  Even the best qualified people had no real way to predict what the activity meant - they could only rely on statistical likelihood based on historical events to discuss what may happen next.  Of the five things Dr. Smith had mentioned leading up to a hydrothermal explosion or supervolcanic eruption, four were present in this case.  The only one that was not noted was an increase in volcanic gasses.  Who knows if the magma movement was more or less routine and the magma was simply able to move more rapidly than is typical through an area where there was minimal resistance, until a after nearly a week a more formidable barrier was finally encountered?  Will this be the end of the quake swarm, or will it resume in the near future and continue for weeks, as some do?  Could these quakes have created new tension instead of releasing it, and a large quake be next?  Might the magma again break through and trigger an explosive event?  I really don't think that, beyond knowing the relative historical frequency of each type of event, anyone can really say what this all means, or what will happen next. 

My smallish mind interpreted what I was seeing and reading as magma movement-related, but that wasn't how Dr. Smith and his colleagues were seeing the same information.  According to Dr. Smith, the earthquake swarm was more of a major seismic event rather than a major volcanic event.   That is, it was related to faults and plate movements mostly and NOT to magma movement.  If anyone is one the fence on this, I say GO WITH THE GUY WHO HAS SPENT 30+ YEARS STUDYING YELLOWSTONE!  Still, I am eager to see anything they come up with concerning this event. And I'll be sure to post whatever I do find, so stay tuned.

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Sunshine on Discovery Bay

Sunshine on Discovery Bay
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