The Ongoing Long Valley Supervolcano Threat- and What Happened There in the 1980's-90's

The swarm of quakes under Mammoth Mountain has tapered off over the past few days, but activity has bubbled up under the SE edge of the resurgent dome, just west of Hot Creek. 18 quakes in 3 hours, the largest was Mag 2.5 with normal-oblique style-faulting.



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CalVO released their summary of last month's swarm activity under Mammoth. They conclude it was likely related to migrating hydrothermal fluids.

Long Valley Caldera and Mono-Inyo Chain: An earthquake swarm occurred beneath Mammoth Mountain, lasting from about February 3-18. Though Mammoth Mountain is the site of frequent earthquake swarms, this was one of the largest since a protracted swarm in 1989.
The February swarm included 166 earthquakes of M1.0 or larger, most at depths of ~5 km below the surface. The largest event was M 3.1 on Feb 5, which was felt by some residents of the town of Mammoth Lakes.
The swarm is likely related to migration of deep-seated hydrothermal fluids. No accompanying changes in surface deformation or gas emissions have yet been detected.
Elsewhere in the region, forty earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum M2.6. No earthquakes M1.0 or greater were detected under the Mono-Inyo chain.

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hey, true american! how are ya?

this is an interesting read, i have known about long valley for a few years now and i have suspected it is at least equally as active as yellowstone. i was not expecting the activity to be higher than yellowstone.

with that said, some of you may know that one of my older daughters lives in santa crus california. she was relating to me her fears and some of her reasons for wanting to move to a much more geographically safe region. meaning a lot closer to where i live now. and one of those fears, is her fear that yellowstone will have another caldrea forming eruption in OUR lifetime.
i told her that yellowstone should be the least of her worries, and that shes actually got a bigger threat pretty much in her back yard. which i was of course talking about long valley.

in the past month alone long valley has had over 300 small quakes.
i do sense a major volcanic eruption could very well happen in our lifetime, which i suspect is long valley. but at the same time i hope not.
thank you for this thread.

a reply to: TrueAmerican

Bumping this thread.


A lot of seismic activity at long valley over the last several months.