Yellowstone Volcano Observatory Monthly Update: July 1, 2020

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

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Length: 00:05:23

Location Taken: WY, US

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Video edited by Liz Westby
 

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- Hi everybody, I'm Mike Poland the scientist in charge at the Yellowstone Volcano Observatory and I'm coming to you with the monthly update for July 1st of 2020. I'm actually at Black Sand Basin which is just across the street from the Old Faithful area. And I'm standing in front of Sunset Lake which is one of the really spectacular features we have in the Black Sand Basin. Now the colors you're seeing behind me are due to a bacteria that likes to live in hot springs and one of the reasons I think this is so amazing is because we're really looking at an area where the heat deep within the earth is intersecting where life is occurring. In fact, the sort of life we see here might have been very similar to the very first life that formed on earth. So a really spectacular intersection that I find absolutely mind boggling. All right, well let's dive in and talk about what happened in Yellowstone during the month of June. The University of Utah seismograph stations which was responsible for the operation and maintenance of the Yellowstone seismic network located 102 earthquakes in the Yellowstone region during the month of June. That's pretty normal for the region where we see typically about 1500 to 2500 earthquakes every year on average. So in fact, we're sort of on the low side of average this month. Now, the largest earthquake of the month occurred on June 5th, mountain time about 10 miles south of Man of Hot Springs. That was a magnitude 2.8. There was also a small swarm of about 17 events that occurred between June 12th and the 15th oh, about halfway between Norris Junction and West Yellowstone. So a pretty average month for earthquakes in the Yellowstone region. Now if we zoom out and look at the greater region you can see that there are continued aftershocks of the tectonic earthquake that occurred on March 31st in central Idaho. So these are not related to Yellowstone but are aftershocks as the fault system there continues to settle following that major magnitude six event. There are also some aftershocks from the magnitude five event that occurred in mid March in the Salt Lake City area. You can see there's many fewer aftershocks. Of course, the larger the earthquake the longer the aftershock sequence will last. So since this was sort of a mid five in the Salt Lake City area, the aftershock sequence is already calming down. Now this was a mid six event in the Idaho area. That aftershock sequence is still quite vigorous and we'll expect it to continue being vigorous for several months, but calming down gradually over time. Turning now to deformation. Let's look at the vertical deformation in the caldera area. Now this is the White Lake GPS station on the east side of the caldera, Sour Creek Resurgent Dome. Each dot is a daily measurement and this spans the past two years. It's vertical deformation, so downward trends indicate subsidence, and upward indicate uplift. You can see this general trend of subsidence of two to three centimeters a year. That's about an inch a year or so. And in the summer of 2019 there was this sort of pause in that subsidence. We see the same thing happening during the summer of 2020. Now, this is probably a seasonal fluctuation related to ground water recharge as the ground gets sort of charged up with water from all of the spring snow melt. But the overall trend is one of subsidence. If we look at a different GPS station, this is on the north side of Yellowstone Lake, also on the Sour Creek Resurgent Dome, that subsidence trend is pretty obvious here through the past two years. So this particular station does not seem as affected by the seasonal trends as the White Lake Station does. The same subsidence trends are also occurring on the west side of caldera. This is the Old Faithful GPS site. That's located on the Mallard Lake Resurgent Dome. And that's sort of a slow subsidence of a couple centimeters, about an inch or so per year, is continuing through this time period. We can see there is a bit of a seasonal fluctuation here as well in 2019. Don't see that quite yet in 2020. And the Norris area we've seen over the past several months really no net change. Norris is one of the more dynamic areas in terms of deformation in the park. It had been rising since 2015, up into 2018, late 2018 it sort of paused and we didn't see a whole lot of change until late 2019 when there was some rather sudden subsidence of a few centimeters, about an inch or so and then since early 2020 there's been no net deformation of the Norris area. So really, over the last few months the patterns of deformation in the Yellowstone area remain largely unchanged. And finally turning to everyone's favorite geyser, Steamboat Geyser in the Norris Geyser Basin. Of course this began becoming a bit more active in 2018 and it's remained quite active since that time. The month of June saw six water eruptions of the geyser. Now this is the temperature record of water coming out of the geyser. Each slow rise in temperature is indicating an increase in minor eruptive activity and it culminates with a spike that indicates a major water eruption. So there were six of these in June. The first on June 3rd, there was another on June 8th, there's one on June 12th, June 18th, June 23rd, and finally on June 29th. So, the Steamboat Geyser remaining just as active as ever. Well, that does it for the monthly update. Now remember, if you have any questions you can always email us at YVOwebteam, that's all one word, at USGS.gov. Thanks for tuning in. Stay safe, stay healthy, and we'll see ya next month. Bye-bye!