Mammoth Lakes earthquake activity jumps

Site of a former super volcano

Mammoth Lakes, California, lies on the edge of the Long Valley Caldera, says Wikipedia. The area around the town is geologically active, with hot springs and rhyolite domes that are less than 1000 years old.

Mammoth Lakes EQs Jump-June 2014

According to the USGS, the Long Valley caldera formed as a result of ‘super’ volcanic eruption about 760,000 years ago. The caldera measures  20 by 10 miles (32 x 16 km) wide.

Ash from this eruption blanketed much of the western part of what is now the United States. The last eruptions inside the caldera occurred about 50,000 years ago.

I’d like to point out that the super eruption of 760,000 years ago occurred near – or at – the Brunhes/Matuyama magnetic reversal. ( See magnetic_reversal_chart/ ){“feed”:”7day_all”,”search”:null,”sort”:”newes t”,”basemap”:”grayscale”,”autoUpdate”:true,”restrictListToMap”:true,”timeZone”:”utc”,”mapp osition”:[[37.369065779358245,-119.10964965820312],[37.763115548102924,-118.55827331542967 ]],”overlays”:{“plates”:true},”viewModes”:{“map”:true,”list”:true,”settings”:true,”help”:f alse}}

Thanks to Bill Sellers for this link

9 thoughts on “Mammoth Lakes earthquake activity jumps”

  1. I live about 45 miles south of Mammoth Lakes and sure hope the caldera is not going to blow up again. Actually, earthquake swarms are not unusual in Mammoth. In the early 80’s there were months of activity and the USGS issued volcanic activity warnings that received nation wide publicity. Nothing came of it except that real estate values in Mammoth plummeted by half and that DID cause a volcanic reaction from property owners. Interesting to note that just north of Bishop there is a volcanic deposit of tufa that is several hundred feet thick. Scientist say it was deposited tens of thousands of years ago in just a few hours. Simply amazing.

    • Jim,
      While I don’t doubt the possibility that a supervolcano COULD deposit hundreds of feet of ejecta in a few hours, the fact this event happened 760,000 years ago begs the question: just exactly HOW do they know? Volcanologists believe supervolcanos erupt differently than typical stratovolcanoes and certainly over longer periods of time, on the order of a thousand years or more. But they definitively know this event occurred in hours? Riiight.

      The same fuzzy math/logic algorithms used to make these determinations is exactly why I can’t definitively trust government scientists who tell me by 2100 we’re going to have a planet 3-5°C warmer than it is today — even though those same scientists tell us the last glacial ice age was a matter of global average temperatures being cooler than now by a mere couple degrees Celsius.

  2. Id be a bit more concerned about the now regular and increasing in force quakes in oklahoma, right now
    just looked in at usgs and theyve had a 4,
    from a place where you never saw anything to a daily event or more for a lot of months now.

    • Strangely enough, as I recall, there was one of the “investigators” of the BP blowout in the Gulf that predicted that because of what BP did in drilling “where” they drilled, that the New Madrid fault line would become more active. I don’t lay this to “local fracking,” but I do believe his prediction has proven to be only to true, which isn’t good since I believe he felt that the 8 size quake could and probably would happen again.

      It’s funny but somehow scientists always find new faults that they hadn’t previously mapped when you get quakes showing up where they had no previous history. Makes you wonder what it is that is causing the deep faults to appear. Maybe the “expanding Earth theory” holds more water than thought.

  3. Caldera’s have long fuses. They take a lots of time to awaken. Mammoth has had these swarms for 100s and possibly thousand’s of years. The last eruption within the caldera was like 10,000 years ago. Scientist’s believe that when the next one occurs, in the Long Valley Caldera, it will most likely be a small scale Phreatic steam eruption..not likely the pictures of Mt St Helen’s
    In the meantime, expect lots of earthquake swarms, like the ones that are over do.

  4. Does anyone know what the super eruption cycle is for Long Valley? How big is the magma chamber and how much has the earths crust moved over the mantle plume and in what direction? How much eruptable magma is in the magma chamber? These quake swarms might be interesting but they could also mean very little on their own.

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