Yellowstone Volcano Observatory Monthly Update: August 1, 2020

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Detailed Description

Mike Poland, Scientist-in-Charge of the Yellowstone Volcano Observatory, gives an overview of activity at Yellowstone during July 2020.
 

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Date Taken:

Length: 00:03:59

Location Taken: Yellowstone National Park, US

Video Credits

Video edited by Liz Westby, Cascades Volcano Observatory, lwestby@usgs.gov
 

Transcript

- Hi, everybody. I'm Mike Poland, the Scientist-in-Charge at the Yellowstone Volcano Observatory and I am here with the update for August 1st of 2020. And I'm coming to you from the Mud Volcano thermal area in Yellowstone National Park in Hayden Valley. In fact this is the Mud Volcano thermal feature right behind me. Just insanely cool. Another cool thing about the Mud Volcano area is that it has the strongest magmatic component in terms of the gases that are released. So the gases here look more magmatic than anywhere else in the park, in fact the gases here are some of the hottest gases coming out of any of the features in the park. And that's because just three and a half miles down, just about five kilometers or so, the magma body is sitting beneath us. Now that magma body is mostly solid, but it still has some dissolved gases in it and those gases percolate up, and that's what we're seeing coming out of the Mud Volcano area here right behind us. All right, well let's have a look at the data and see what happened during the month of July. July of 2020 was a very slow month for earthquakes in Yellowstone. University of Utah Seismograph Stations, which is responsible for the operation and maintenance of the Yellowstone Seismic Network recorded only 47 earthquakes in the region during the month. The largest occurred just before midnight on July 3rd on the east side of the park. This was a magnitude 1.7 and there was no swarm activity in the region during the month. This sort of variation is typical. Months with very low numbers of earthquakes followed by months with higher numbers of earthquakes. This very good demonstration of the dynamic nature of the Yellowstone region. Zooming out a little bit we can see some of the aftershock sequences that occurring due to past tectonic earthquakes. There was a mid-magnitude five earthquake in the Salt Lake City area in mid-March and of course a 6.5 in central Idaho on March 31st. Both of these sequences continue to be followed by aftershocks here. Fewer numbers of aftershocks in the Salt Lake City region because that was a smaller earthquake. Smaller main shock and so the aftershocks will peter out more quickly. Because the Idaho earthquake was a much stronger main shock, the aftershock sequence will last longer, certainly throughout the rest of this year and perhaps longer. Deformation in the Yellowstone region has remained relatively steady over the last several months. This is vertical deformation at the White Lake GPS Station on the east side of the caldera, Sour Creek Resurgent Dome. This time series starts in 2018 and goes up to the present time and each one of these circles represents one day of data. Over this two and a half year time span, this downward trend indicates subsidence, or sinking of the ground. Now this subsidence has been occurring since 2015 and the rate has been pretty steady, about 2 to 3 centimeters, it's about an inch or so per year. So that's continuing. Looking at the west side of the caldera in the Mallard Lake Resurgent Dome, there's a GPS site near Old Faithful showing the exact same sort of trend, this downward trend over time occurring at rates of a couple centimeters, about little less than an inch per year. So no changes in overall caldera deformation. Looking at the Norris Geyser Basin, of course that's a bit different because we had uplift from 2015 into late 2018. In late 2018 that uplift plateaued and we didn't see much change through much of 2019, and then late 2019 a bit of subsidence and since the beginning of 2020 there really hasn't been much deformation in the Norris region. So the trends that we've seen over the last several months in terms of deformation have been continuing. And finally, turning to everyone's favorite geyser, we had six, count 'em, six eruptions of Steamboat Geyser during the month of July. July 3rd, July 9th, the 13th, the 19th, the 24th, and the 30th. So Steamboat just remains as active as ever. Well that does it for the update for August 1st of 2020. Remember if you have any questions, you can always email us at yvowebteam, all one word, @usgs.gov. Hope everyone is staying safe and healthy and we'll see you next month. Take care.