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| "The Coso Volcanic Center has become active since the SA EQ http://www.thegoldenthread.info/phpBB3/viewtopic.php?f=47&t=1549 |
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| Author: | Siam [ Sat Feb 27, 2010 8:42 pm ] |
| Post subject: | "The Coso Volcanic Center has become active since the SA EQ |
-------------------------------------------------------------------------------- From Frank Condon of Syzygy @ http://camel.he.net/~syzygyq/new_site// ... 18.new#new "The Coso Volcanic Center is the location that has become increasingly seismically active since the M8.8 earthquake in South America. This is where geothermal energy related to a magma chamber is currently being tapped for power generation" . . . . . . . . . . From http://en.wikipedia.org/wiki/Coso_Volca ... Geothermal The Coso Volcanic Field is located in southeastern California, at the western edge of the Basin and Range geologic province. Initiation of volcanism at Coso preceded the onset of Basin and Range crustal extension there, as expressed by normal faulting. The earlier of the two principal periods of volcanism began with the emplacement of basalt flows over a surface of little relief. Then, during the ensuing period of approximately 1.5 million years, eruptive activity included chemically more evolved rocks erupted upon a faulted terrain of substantial relief. Following a 1.5-million-year hiatus with few eruptions, a bimodal volcanic field of basalt lava flows and rhyolite lava domes and flows developed on Basin and Range terrain of essentially the same form as today's landscape. Many of the young basalt flows are intercanyon, occupying parts of the present-day drainage system. . . . The Coso Volcanic Field is also well known as a geothermal area. Fumaroles are present along faults bounding the rhyolite-capped horst and locally within the rhyolite field. A multi-disciplinary program of geothermal assessment carried out in the 1970s defined a potential resource of 650 megawatts electric with a nominal life span of 30 years. Judged by the youthfulness of the rhyolite lavas and by a zone of low seismic velocity crust roughly beneath the rhyolite, a magma body may be the source of thermal energy for the geothermal system. . . . The Coso Volcanic Field is one of the most seismically active regions in the United States, producing dozens of tremors in the M1 and M2 range each week. Tremors in the M3 range occur at a rate of 2-6 per month and M4 quakes occur two-three times each year. Recent activity in the M5 range happened in 1996 and 1998 when tremors of M5.3, M5.1, M5.2, and M5.0 occurred with a day of each other. These tremors were actually recorded along the eastern side of the Coso Volcanic Field, 15 miles (24 km). September 30, 2009 to October 6, 2009 there have been 429 earthquakes ranging from 0.1 up to a 5.2. Some days have activity just about one every minute. On October 2, 2009 there were three earthquakes (5.2, 4.7, and a 4.9) all with in one hour of each other Earthquake swarms are common in the Coso area, often producing hundreds of tremors over periods of time as short as a few days. This kind of brisk and robust seismic activity is common in volcanic areas, such as Long Valley Caldera located near Mammoth Lakes, and Yellowstone Caldera at Yellowstone. The Coso Volcanic Field shows stunning examples of volcanic activity, probably last active 30-40,000 years ago, but ash emission and small cone building episodes may be Holocene (>10,000 years) in age. |
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