Leslie Gordon: Hello and welcome to the U.S. Geological Survey CoreCast. I'm Leslie Gordon and today, I am speaking with Dr. Jake Lowenstern, the Scientist-In-Charge of the USGS Yellowstone Volcano Observatory. Hello Jake. Thank you for spending time with us.
Jake Lowenstern: Thanks.
Leslie Gordon: Well, I understand that we've all seen a lot of activity in the Yellowstone area, earthquakes and such. Can you explain to our listeners what you've been observing and what's going on?
Jake Lowenstern: Starting on the evening of December 26, there was an earthquake swarm that involved over 500 earthquakes over the following week or so. And swarm is when you have instead of a bigger earthquake followed by lots of smaller aftershocks, as we call them that much smaller, swarm is a packet of earthquakes that is close in time and space in one particular area, one particular time.
And there isn't any larger earthquake relative to any of the others.
Leslie Gordon: So have you seen anything else in addition to this large swarm of earthquakes?
Jake Lowenstern: So far, it's just been seismic activity. There hasn't been any other changes in the surface thermal features at Yellowstone. There hasn't been any obvious ground deformation that anybody has seen up to this point. But some of the earthquakes were up to magnitude 3.9 I think was the largest and probably 10 or so were felt by the people living in the Fishing Bridge area at the north end of Yellowstone Lake.
Leslie Gordon: Is this anything that we should be concerned about or what do these swarms of earthquakes mean?
Jake Lowenstern: Well, swarms at Yellowstone are a very common mode of earthquake occurrence. Every year we have a number of swarms. Usually they are smaller than this one. This is very energetic swarm and probably the most energetic swarm since 1985.
So it's not unprecedented. On the other hand, it's an energetic swarm. People were feeling it.
And it's an area where there are thermal features and so anytime, there's earthquakes near thermal features we worry about the possibility of explosions of the groundwater system.
Leslie Gordon: And is there a large probability of explosions or other activity? Is this something that we should be worried about?
Jake Lowenstern: It's always something that can happen. Anytime you live in an area where there are earthquakes, where there is volcanic activity or where there is these hydrothermal features, there are geological hazards associated with them. And so that's why we're there is to monitor the system, to see what's happening and to let the public know if there's any danger for any of the people who are in that area.
Leslie Gordon: So will you and your colleagues at the University of Utah and the Yellowstone National Park are continually monitoring the situation and you would let the public know should anything arise that's unusual?
Jake Lowenstern: Sure. The Yellowstone Volcano Observatory is set up as a partnership to provide warnings. That's what we're there for.
And so we get the information. We share it with the park and with the public as we learn it. And in this case, people found out about the earthquake swarm. People were able to see the events are they were happening on the Internet. And there was in this case, no need to get people out of the way because we didn't think that the earthquakes are going to cause any harm.
Leslie Gordon: OK. Is the earthquake activity continuing like we saw it a week ago or what's happening today?
Jake Lowenstern: No, most of the activity curtailed in the first couple of days of this year. And so right now, there's really very little earthquakes happening at Yellowstone.
Leslie Gordon: Well, let me hear a little bit of background about Yellowstone. I think most people know that Yellowstone is an ancient volcano. Can you tell us a little background about that?
Jake Lowenstern: Yellowstone has been a very very active volcano over the last couple of million years.
Some of the very largest eruptions that we know about on earth have come out of the Yellowstone volcanic center. The most recent of these really large events was about 640,000 years ago. It formed at the Yellowstone called their remnants and ash over much of the United States. These kinds of eruptions are sort of as global events. There has been a number of volcanic eruption since then are much smaller in scope and have fairly large lava flows but not the sort of event that would shake the nation or would have any kind of global effect.
And so, the last of those volcanic eruptions was about 70,000 years ago. Since that time, we've had many large earthquakes. We've had steam explosions, some of which have caused craters that are couple of miles across even in some cases generally much smaller than that.
So these are all the sorts of things that can happen and they are the kinds of things that we keep an eye on.
Leslie Gordon: So a lot of the things that Yellowstone is famous for, all the hot springs and boiling mud pots and the geysers, these are indications of the remnants or the fact that it's still very hot underground.
Jake Lowenstern: The Yellowstone hotspot is what it's called and that is an area of melting in the earth's mantle. And that melting creates the basaltic magma that rises into the crust. And that melts part of the crust and you have a magma chamber. There's actually liquid rock and crystals that are sitting, maybe four, five miles beneath the surface, that releases a lot of heat. That heat rises. It boils the groundwater system in some cases and creates all these fabulous thermal features that we see at the surface of Yellowstone.
Leslie Gordon: So if I want to know more information and I want to keep up to date and see about these earthquake swarms, how can I found out more information and watch what's happening at Yellowstone?
Jake Lowenstern: Well there's a number of places. One is the Yellowstone Volcano Observatory Website. But also we are using the data provided by our partners at the University of Utah.
They have a website that shows all the seismic data. And then the USGS Earthquake Hazards Program also mirrors the earthquake data from the University of Utah. So, all of these locations will provide you with up-to-date information on earthquakes at Yellowstone.
Leslie Gordon: Can you tell us what the URL is for the Yellowstone Observatory?
Leslie Gordon: Jake, what are some of the challenges that you face while monitoring hazards at Yellowstone?
Jake Lowenstern: One of the amazing things that we see during these kinds of events is how many people are out there looking at the data and trying to interpret it on their own. Sometimes they do a great job of it. Sometimes they confuse other kinds of signals like wind, and snowmobiles and other features that might look like earthquakes but indeed might not be earthquakes.
So it's a challenge for us, not only to keep up with the science, but to keep up with the sort of furor out there of people who are trying to do their interpretations on the side and to keep everybody happy and everybody thinking about the real end game of making sure that people are safe.
Leslie Gordon: Thank you. Jake Lowenstern, thank you very much for chatting with us today. Thank you to our listeners for tuning in to CoreCast. For links and other resources about current activity in Yellowstone, please go online to www.usgs.gov/podcasts or volcanoes.usgs.gov/yvo.
CoreCast is a production of the U.S. Geological Survey Department of Interior. Until next time, I'm Leslie Gordon and thanks for tuning in.