Thursday, December 1, 2011

Small Quake Swarm At Mono Lake Volcano (California)

Mono Craters, California
12/1/2011


A series of small quakes ranging from magnitude 1.9 to 2.5 occurred and is ongoing today just east of the shore of Mono Lake. The quakes were relatively shallow, from 5km underground to less than a quarter mile. The quakes were clustered in a somewhat linear direction, making it very possible this is just tectonic stress, but as is the case for most volcanoes, there is always the possibility for magma movement. The events have not undergone review as of yet by scientists, so speculation about the quakes is useless. A picture is posted below:



The Mono Lake, and surrounding Inyo Craters/Mammoth Mountain/Long Valley area are all volcanic areas and small quakes here are quite common. Every once in a while there is a scare in the area when it comes to the specter of an eruption. In the early 90's, tree kill occurred at Mammoth Mountain, and caused at least one fatality due to the inhalation of CO2 gases released from the ground. This was thought by scientists to be related to dike intrusion under Mammoth Mountain.

Mono Lake has had at lest one eruption in historical time, the last being somewhere between 100, and 250 years BP (Before Present). During this eruption, a rhyolitic cryptodome grew underneath the lake, resulting in the formation of spectacular "Tufa Towers" that stand around the rim of the lake like gigantic garden gnomes. The water in the lake is high in arsenic, and it was recently discovered that certain microbes in the water actually feed on and process arsenic, much to the amazement of biologists. This of course bolsters NASA's stance that where life can exist, it will.

At present nobody has raised the alert level at Mono Lake or sounded any alarms, so there is most likely no risk of any sort of eruption at this time. However the swarm just started today and it's probably worth keeping an eye on, as this area is home to some pretty large volcanoes. As of this morning, this concentrated area of earthquake activity has recorded about 8 tremors, which have all occurred within a few hours of themselves, with another one just having occurred as I am writing this.

From Smithsonian GVP:


"The Mono Lake volcanic field east of Yosemite National Park and north of the Mono Craters consists of vents within Mono Lake and on its north shore. The most topographically prominent feature, Black Point, is an initially sublacustral basaltic cone that rises above the NW shore and was formed about 13,300 years ago when Mono Lake was higher. Holocene rhyodacitic lava domes and flows form Negit and parts of Paoha islands off the northern shore and center of the lake, respectively. The most recent eruptive activity in the Long Valley to Mono Lake region took place 100-230 years ago, when lake-bottom sediments forming much of Paoha Island were uplifted by intrusion of a rhyolitic cryptodome (Stine, in Bailey et al. 1989). Spectacular tufa towers line the shores of Mono Lake."

2 comments:

  1. 12/16/2011

    I was at Mono Lake at approximately 1pm, when I heard some loud rumbling, eruption type of sound and then saw clouds of smoke coming from behind some mountains east/ne from mono lake. Any idea on what that was from?>

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  2. I wish I knew, I wasn't there, but if what you're saying is true, could be some activity in the area. That's quite intriguing. You may wish to contact USGS and issue a report so they can investigate.

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