Thursday, May 1, 2008

Whole Lotta Shakin' Goin' On

In case you haven't felt the news, there's currently a very interesting geological event going on in Reno right now. HERE'S the mass-media story. But cute stories about kids knowing more about earthquakes than their teachers don't really relay the import of the situation, and Reno is only part of the story.

An earthquake “swarm” is an episode with many earthquakes in which the largest earthquake does not occur at the beginning of the episode and in which the largest earthquake is not substantially larger than other earthquakes of the episode. Earthquake swarms generally continue for weeks, months, or even longer, without the occurrence of a substantially larger event. This distinguishes a swarm from a sole event with aftershocks. Earthquake swarms occur in a variety of geologic and tectonic settings. Swarms are rare, and usually (but not always) tied to volcanic activity.

But Swarms of Earthquake Swarms are unheard-of. Here are the important swarms all happening within the last couple of months:

Reno's swarm is currently at 350+ events. Reno is currently moving (Thanks to the North American Plate movement) to the Northwest at the rate of 11mm per year. This is causing a great deal of pressure at the junction of the North American Plate and the Pacific Plate: they are SWALLOWING the Juan de Fuca Plate and the Cocos Plate, to the North and South, respectively.

Cerro Prieto Volcano and Geothermal Field: The meeting point of the East Pacific Rise and the slip-strike of the San Andreas Fault, at the Northern Edge of the Cocos Plate. Swarm of 250 events over 3 weeks in February 2008. If a major quake is triggered here, pretty much all of the Colorado River delta will flood, up to and including the Salton Sea, which is below sea level.

Oregon Coastal Zone: Unique swarm of 600+ EVENTS occured OVER THE LAST MONTH, just east of the Cascadia Subduction zone at the boundary of the Juan de Fuca Plate, which has the potential for a mega quake greater than that of the New Madrid Fault in Missouri (Side note: the new madrid fault is responsible for the 3 of the 5 largest quakes in the contiguous United States. Read more HERE.) The last mega-quake at the Cascadia Subduction Zone (January 26th, 1700) was a ~9.0 and dropped the coastline in some parts of Washington by 5 feet. Yes. I said 5 feet. Estimates and Pattern studies put cycle periods on mega-quakes in the area at 400-600 years.

This is great news for guys like me who have been waiting for a major earthquake to lower house values in California. I just hope that a mega-quake doesn't lower house heights in California to the point that we end up living in THIS FLOATING DEVELOPMENT.

That would really suck.


Ignoramus said...

How come you know so much about earthquakes and tectonic plates?

The Vitruvian Duck said...

Because I have, in the ironic twist of age, become the guy I used to beat up in High School.