Tuesday, December 28, 2010
California: Quake Swarm at Salton Buttes Volcano
Today we're having a swarm of micro-quakes at the Salton Buttes volcano, which is an active volcano listed by the USGS as one. It has vents that vent through thousands of feet of sediment, which creates the Salton Sea mud volcanos and mud pots. These mud pots are deeply buried volcanic vents that you can actually walk up to. Anyways, back to the micro-quakes we're having. You will see a cluster of them in the middle of this map, right on the south end of the big lake. A bit over a week ago, we experienced a similar earthquake swarm just south of that, in Imperial. And a week ago, one near Ocotillo, way to the southwest of the Salton Sea, near the US-Mexico border. All of these recent swarms are related to the rift zone that they lie in. The tectonic plates are pulling apart here, thinning the crust as they do. Someday in the far future, the part of Southern California that lies on the Pacific plate with be divided from the mainland, and water will be between these sections of California.
There is a body of magma about four miles under the Salton Buttes, and a cooling magma pipe about a mile below the Buttes. One question comes to mind, are these small quakes something do do with moving magma, or contracting magma as it cools, or are they due to moving hot water and steam? There is a hydrothermal plant next to this volcano, just like there is one next to Cerro Prieto volcano, to the South, In Mexico. This is a good question that needs to be pondered. One way of finding out some answers is to look at the shape and nature of the waveforms from a seismograph, which can be found clicking around tise USGS page. Just click on a quake, then scientific at the top of the specific earthquake page. If the waveform is fuzzy looking, and less sudden looking, it's probably not related to a crack in the rocks, but moving fluids. You can also click on a specific quake and look at the depth of the quake. If it at the same depth of the magma chamber, about 4 miles down, it may have something to so with that magma indeed!
So click below and click around the quakes, and find your own answers. Have fun!
California-Nevada Fault Map centered at 33°N,116°W