Yellowstone Volcano Observatory Monthly Update: April 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 March 2020.


Date Taken:

Length: 00:04:47

Location Taken: WY, US

Video Credits

Video edited by Liz Westby


- Hi, everybody. I'm Mike Poland, the Scientist-In-Charge at the Yellowstone Volcano Observatory, and I am here with the monthly update for April 1st, 2020, coming to you from my house. Of course, many of us are working from home these days. And, first and foremost, I'd like to wish everyone safety and health. It's certainly challenging times. Hope everyone is well. Before we dive into the data, I wanted to discuss a bit of the earthquake activity that's been occurring in the Western U.S. Of course, we had the magnitude 5.7 near Salt Lake City on March 18th, and then just yesterday, on March 31st, we had a magnitude 6.5 in Idaho. And there's understandably some questions about whether or not these are related to Yellowstone. I'm happy to report they're not. These are actually related to mountain building processes in the Western U.S. The Western U.S. is being tectonically stretched, and that creates that very unique topography we see there, where there's alternating mountains and then valleys. As that stretching occurs, you get mountain building and valley formation, and the earthquakes that we've seen in Salt Lake City area, and then also near Challis, Idaho, are representative of that kind of process. Those sorts of earthquakes are not uncommon for the region. For example, there was a magnitude 6.9 in the same general area, central Idaho, back in 1983. That was the Borah Peak earthquake. So not related to Yellowstone. Related to the tectonic extension of the Western U.S., but still a very good reminder that strong earthquakes can happen throughout the Western U.S., and preparation's important. With that, let's look at what happened in Yellowstone during the month of March. The University of Utah seismograph stations, which is responsible for the operation and maintenance of the Yellowstone seismic network, recorded 111 earthquakes in the Yellowstone region during the month of March 2020. The largest event of the month was a magnitude 3.1 on March 31st just to the left of the park boundary on the east side of Hebgen Lake. There were also two swarms in Yellowstone during the month. The first was a small swarm of 15 earthquakes that occurred between March 5th and March 14th. The largest event of this swarm was a magnitude 1.7. There was another swarm of 19 events, the largest being a magnitude 2.1, that occurred between March 21st and 29th. This sort of swarm seismicity and the overall number of earthquakes in the Yellowstone region for the month is pretty normal for Yellowstone. Turning out a deformation, this is a plot of GPS vertical component of motion at the White Lake GPS station, which is located on the Sour Creek resurgent dome on the east side of the caldera. Each data point is one day of data, and the plot spans two years. This downward trend is showing subsidence of this site over that two year time period by about a few centimeters, two to three centimeters per year. There are some little fluctuations in that, but the overall trend is subsidence. If we move to the other side of the caldera, the Mallard Lake resurgent dome near Old Faithful, we see the same overall trend of subsidence over the last two years at a rate of a couple of centimeters per year, and this has been ongoing since 2015. So caldera subsidence is continuing. Moving to the Norris area, Norris Geyser Basin just north of the caldera, that had actually been uplifting between 2015 and 2018. And you can see the tail end of that uplift right here, through mid-2018. But by late 2018, things had stopped and settled down, and there wasn't a whole lot of up or down motion at Norris through late 2018 and much of 2019. In September of 2019, there was a small episode of subsidence, amounting to about three centimeters. It stopped by the start of 2020, and there hasn't been a whole lot of up or down motion since the beginning of 2020. So Norris, for the last few months, has remained relatively stable, while the caldera has continued to subside. And finally, we'll take a look at Steamboat, everybody's favorite geyser. Steamboat had three water eruptions during the month of March. The first was right here; this is a temperature record of the Steamboat outflow channel, and that spike right there is an eruption that occurred on March 6th. There was another eruption right here on March 15th, and, finally, the last eruption of the month on March 24th. You can see these variations are normal air temperature variations, and then you can see increasing levels of minor activity. That's what all these little wibbles are prior to each major eruption. And we're starting another cycle soon. We would expect to see another major eruption of Steamboat following the pattern that had been established over the last couple of years now. Remember, Steamboat burst back to life in March of 2018. Well that does it for this month's Yellowstone update. Remember, if you have any questions, you can feel free to email us at yvowebteam, that's all one word, We're also on social media under the name USGSVolcanoes. That's also one word. Hope you're all happy, safe, and healthy out there, and we'll see you next month. Take care!