Yellowstone Volcano Observatory Monthly Update for December 2020

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Detailed Description

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

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Length: 00:05:15

Location Taken: Vancouver, WA, US

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Video edited by Liz Westby
 

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- Hi everyone, I'm Mike Poland, the Scientist-in-Charge of the Yellowstone Volcano Observatory, and I'm here with a monthly update of Yellowstone activity for January 1st of 2021. That's right, 2020 is finally over. And even though it may not have been the greatest year for many of us, it was a distinctly average year for Yellowstone activity. Now, typically in a given year, we see 1,500 to 2,500 earthquakes in the Yellowstone region. And in 2020 we saw 1,718, so right in that average range. There were also 23 seismic swarms recorded throughout the year in the Yellowstone region. And those 23 swarms were responsible for about 50% of the total earthquakes that occurred during the year. And that's also very much average for a given Yellowstone year. Deformation-wise, we didn't see many changes at all. The Yellowstone Caldera continued to slowly subside by about two to three centimeters per year. That's about an inch per year, and that's been going on since 2015 and in the area of the Norris Geyser Basin, we didn't see any deformation at all. And then finally, in terms of geyser activity, the really neat activity was the Giantess Geyser which is near Old Faithful sprang to life in August and then again in September with a couple of eruptions. Those were the first eruptions in six years. So that's pretty neat for Giantess and then Steamboat Geyser in the Norris Geyser Basin didn't seem to know what year it was at all. In 2019, Steamboat set a record for the number of eruptions in a calendar year with 48. And guess what? In 2020, 48 eruptions then as well. In 2019, the shortest time period between Steamboat eruptions was three days and the longest was 17 days. And guess what? In 2020, the shortest was three days. The longest was 17 days. So Steamboat had a very, very similar 2020 compared to 2019. So average activity over the course of the year, all normal for Yellowstone. Now let's take a deeper dive into what happened during the month of December 2020. The University of Utah Seismograph Stations, which is responsible for the operation and maintenance of the Yellowstone seismic network recorded 292 earthquakes during the month of December, 2020. The largest was a magnitude 2.6 event that occurred in the Northwest part of the park between Hebgen Lake, Montana, and Norris Junction in Yellowstone National Park. Now, also during the month, there were three seismic swarms that occurred. The first was between December 1st and the 14th right here, sort of in the middle of Yellowstone Lake. This was right on the fault that was formed in the last caldera collapse, when Yellowstone Caldera formed 631,000 years ago. 148 earthquakes, part of this swarm, the largest was a magnitude 2.6. There was a smaller swarm of about 37 earthquakes that occurred on December 7th, maximum 1.8, and that was just North of West Thumb. And finally there was a swarm of 48 earthquakes that occurred December 24th to the 25th, just north of the Old Faithful area. And the maximum here was a magnitude 2.0. In terms of deformation, we haven't seen many changes in the Yellowstone region for quite some time. This is vertical deformation at the White Lake GPS Station. This is on the east side of the caldera, the Sour Creek resurgent dome. Each one of these dots is a day's worth of data, and when you see the trends going down, that means subsidence, or the ground sinking. You can see aside from some seasonal variations, the ground has consistently gone down by about two to three centimeters per year. That's about one inch or so per year. And this graph here spans two years. If we look at the west side of the caldera and the Mallard Lake resurgent dome, here's the GPS Station that's located near Old Faithful. And this same trend is apparent, a slow subsidence, slow sinking of the ground, and the Mallard Lake resurgent dome at a rate of a couple centimeters per year. And finally, turning to the last two years of vertical deformation at the Norris Geyser Basin, aside from this small subsidence event at the end of 2019, there really hasn't been much change over the course of 2020. So not much deformation at all happening at Norris. And now to everyone's favorite geyser, Steamboat Geyser in Norris Geyser Basin, they were two eruptions at Steamboat. This is the temperature record of water in the Steamboat outflow channel. You can see these rises in temperature as the geyser starts to heat up and get active, lots of minor eruptive activity, and then the spike, and then the temperature drops as water drains out of the area, and then the geyser eventually refills and becomes active again. There were two water eruptions of Steamboat in the month of December, on December 11th and then again on December 20th. Now the record ends here in late December, because power was lost to the Norris Museum. But we know from other data that the geyser did not erupt at the end of the month, although you can see it was clearly recharging and on its way to erupting. So we should expect another Steamboat eruption early in 2021. Well that does it for the Yellowstone Volcano Observatory update for January 1st of 2020. Now remember if you have any questions, you can feel free to email us anytime at yvowebteam, all one word, @usgs.gov. Hope everyone is enjoying a good start to 2021. Hope it's a better year for everyone. Stay safe, stay healthy. We'll see you next month. Take care.