Sunday, May 10, 2015

Long Series Of Quakes At Mono Lake

Mono Lakes Eastern shore has been shaking lately. A lot. This has been going on for around a week now, as I have kept my eyes on it. Nobody is writing anything particularly useful about the goings-on there, so I thought it would be good to mention it.

Screenshot of Mono Lake quake swarm from Google Earth with USGS Real-time quake overlay.
The Eastern shore of Mono Lake is experiencing a couple of small shallow quake swarms, although some quakes have reached magnitude three or higher. This is likely hydrothermal or tectonic in nature, and not volcanic. The area does have cold springs, and an active magma chamber below, so it is likely that this is what is referred to as a spasmodic swarm. Plainly, the shifting of fluids within the upper crust due to hydrothermal changes.

What this means isn't certain for Mono Lake, which had it's last spate of activity some 100-200 years ago, when a rhyolitic cryptodome uplifted lake sediments to form the large central island. So the volcano absolutely does have a fairly recent history of activity. Tufa towers from hot and cold springs line the lake, attesting to its continued heat below.

Quake swarms like this are very common in the area however, as it is also a very tectonically active zone with many criss-crossing faults. It is as likely a scenario as a spasmodic swarm, and this could simply be crustal adjustments due to fault stress.

In any case the swarm is interesting and of note, so I'm keeping my eye on it. It's probable that nothing will happen at Mono Lake as a result of this and life will go on. But you never know with volcanoes, and this is a fairly large one. 

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