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  • richardmitnick 7:03 am on August 20, 2018 Permalink | Reply
    Tags: , , Volcano science,   

    From Discover Magazine- “Wilderness vs. Monitoring: The Controversy of a New Seismic Network at Glacier Peak” 


    From Discover Magazine

    August 19, 2018
    Erik Klemetti

    Glacier Peak in Washington. Wikimedia Commons.

    One of the most potentially dangerous volcanoes in the Cascades is Glacier Peak in Washington. It produced the one of the largest eruptions in the past 20,000 years in this volcanic range that spans from British Columbia to California. Multiple eruptions around 13,500 years ago spread ash all the way into Montana. Over the last 2,000 years, there have been multiple explosive eruptions that have impacted what became Washington state and beyond. Put on top of that the many glaciers on the slopes of Glacier Peak that could help form volcanic mudflows (lahars) during a new eruption, and you can see that Glacier Peak is a real threat.

    Yet, even with this hazard posed by the volcano, there is very little in the way of monitoring equipment on the volcano. Currently, there is a lone seismometer on the volcano to measure earthquakes, one of the most important pieces of information needed to monitor volcanoes.

    The lone seismometer at Glacier Peak. USGS. https://volcanoes.usgs.gov/volcanoes/glacier_peak/monitoring_earthquakes.html

    A single seismometer is better than no seismometer, but it can only give us so much information. Without a network of at least 3 seismometers (a“seismic network”), we can really only measure if earthquakes are occurring at the volcano and not exactly where and how far beneath the volcano the temblors are happening. This is what is installed at a truly restless volcano like Mount St. Helens.

    These two pieces of information — location and depth — are vital for understanding what might be happening at the Glacier Peak if any earthquake swarm were to happen. Otherwise, we might have difficulty differentiating between earthquakes happening due to fault motion near the volcano or shallow changes in the hydrothermal system in the volcano rather than magma moving into the volcano from deep below.

    So, it might seem to be a no-brainer that new USGS seismic stations should be set up on Glacier Peak. However, that’s where things get messy. Glacier Peak is within designated US Forest Service Wilderness area, so modification and use of the land are very tightly regulated and restricted. This is rightly so — we need to protect our wilderness from encroaching development or resource exploitation by people who don’t value a wild America.

    The problem becomes that a seismic station, a fairly small installation that might have a 3 by 3 meter footprint, still disrupts wilderness in order to build the station as it requires the seismometer to be buried and secured to a stable platform (like rock or poured concrete). Additionally, although many stations are solar, they do require back-up batteries that need to be changed … and if there are no roads and trails in the wilderness, getting material to the station is next to impossible.

    In order to perform repairs and resupply batteries, helicopters will be needed, so ideally, a helicopter pad near the seismic stations is needed for safe operation. This is a bigger deal as a helicopter pad might take up a few hundred square meters. It is this sort of disruption that has the Wilderness Watch speaking out against the installation of new seismic stations at Glacier Peak.

    See the full article here .


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  • richardmitnick 8:21 am on November 2, 2017 Permalink | Reply
    Tags: , , , Twin Yellowstone super-eruptions altered global climate, Volcano science   

    From EarthSky: “Twin Yellowstone super-eruptions altered global climate” 



    November 2, 2017
    Eleanor Imster

    The Yellowstone supervolcano’s last eruption wasn’t a single event, but 2 closely-spaced eruptions that put the brakes on a natural global-warming trend, says a study.

    The gorgeous colors of Yellowstone National Park’s Grand Prismatic hot spring are among the park’s myriad hydrothermal features created by the fact that Yellowstone is a supervolcano – the largest type of volcano on Earth. Photo via Windows into the Earth by Robert B. Smith and Lee J. Siegel

    The Yellowstone supervolcano’s last catastrophic eruption, about 630,000 years ago, was not a single event, but two powerful and closely-spaced eruptions, according to a new study. The super-eruptions were powerful enough, the researchers say, to slow a natural global warming trend that eventually led the planet out of a major ice age.

    For the study, presented at the Geological Society of American’s annual meeting in Seattle on October 25, 2017, a team of geologists from the University of California Santa Barbara (UCSB) analyzed two layers of volcanic ash discovered in seafloor sediments off the coast of Southern California. These layers of ash, sandwiched among sediments, bear the unique chemical fingerprint of Yellowstone’s most recent super eruption. and contain a remarkably detailed climate record of the violent events that formed the vast Yellowstone caldera – or cauldron-like crater – that we see today.
    UCSB geologist Jim Kennett said in a statement:

    “We discovered here that there are two ash-forming super eruptions 170 years apart, and each cooled the ocean by about three degrees Celsius.”

    Read more about the research here.

    By comparing the volcanic ash record with the climate record of single-celled marine animal fossils, it’s quite clear, Kennet said, that both of these eruptions caused separate volcanic winters, when ash and volcanic sulfur dioxide emissions reduce the amount of sunlight reaching Earth’s surface and cause temporary cooling. According to the study, the onset of the global cooling events was abrupt and coincided precisely with the timing of the supervolcanic eruptions.

    These cooling events occurred at an especially sensitive time, Kennet said, when the global climate was warming out of an ice age and easily disrupted by such events. But, Kennet added, each time, the cooling lasted longer than it should have, according to simple climate models. He said:

    “We see planetary cooling of sufficient magnitude and duration that there had to be other feedbacks involved.”

    These feedbacks might include increased sunlight-reflecting sea ice and snow cover or a change in ocean circulation that would cool the planet for a longer time.

    Bottom line: New research suggest that the Yellowstone supervolcano’s last eruption wasn’t a single event, but 2 closely-spaced eruptions that slowed a natural global-warming trend.

    See the full article here .

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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

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