
Mount Jefferson, left, and Mount Hood, Sept. 5, 2022, both part of the Cascade range. According to the U.S. Geological Survey, both volcanoes show signs of being active, though they haven't erupted in centuries.
Jonathan Levinson / OPB
There’s a lot that researchers still don’t know about volcanoes. But they do expect volcanic eruptions to coincide more often with other natural disasters, like floods and wildfires, as the climate continues to warm. Research from Portland State University shows that the increasing frequency of extreme weather events means they’re more likely to occur at the same time as a volcanic eruption – creating “compound disasters” that will challenge emergency management officials. The study is part of a new collection of scientific essays that assesses how volcano science has evolved over the past 30 years, and where it might go next.
Jonathan Fink is a professor of geology at PSU. He co-edited the collection, and joins us to talk about how volcanic eruptions might factor into future disaster management.
Note: This transcript was computer generated and edited by a volunteer.
Dave Miller: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Dave Miller. There is a lot that researchers still don’t know about volcanoes, but they do expect volcanic eruptions to coincide more often with other natural disasters like floods and wildfires as the earth continues to warm. Research from Portland State University shows that the increasing frequency of extreme weather events means they are more likely to occur at the same time as a volcanic eruption, creating compound disasters that could challenge emergency management officials. The study is part of a new collection of scientific essays focused on how volcano science has evolved over the past 20 years and where it might go in the next 10 years. Jonathan Fink is professor of geology at PSU. He co-edited the collection, and he joins us now. It’s great to have you on the show.
Jonathan Fink: Thanks, Dave. Very nice to be here.
Miller: I want to start with the paper you wrote not too long ago exploring the intersection of volcanoes and other natural disasters. What’s a recent example of that happening?
Fink: The best example is Mount Pinatubo in the Philippines, which erupted in the early 90s. [It] had a huge explosive eruption – one of the largest of the 20th century. That eruption happened to coincide with the arrival of a typhoon in that part of the Philippines. The eruption put out a huge volume of ash that coated everything in the vicinity. Then the monsoon came in with a huge amount of rainfall, generating mud. These mud flows then went throughout the region, flowing down the river channels and causing an additional amount of destruction. That was probably the most graphic case we’ve had in recent years of how these two different, caused disasters can coincide and cause even more of a problem for society.
Miller: That’s kind of the physical reality of what happened. What lessons should we draw from it?
Fink: I think one of the lessons is that preparing for volcanic eruptions is getting more complicated because of these independent problems that could be around because of climate change. The people who normally would study volcanoes, or volcanologists like myself, who learn about how geology works and how a volcano gets active and quiets down, we don’t normally study the weather or flooding or other kinds of natural disasters that might be coinciding with the eruptions. So I think one of the main things is that the training needs to be broader. And the people who are gonna be responsible for the societal responses to volcanic eruptions need to be able to think about other activities that are going on and be able to communicate with the people who are responsible for addressing those.
Miller: This is the climate change driven natural disasters, the potential for them increasingly to happen at the same time as a volcanic eruption. But could climate change itself impact the likelihood of particular eruptions?
Fink: Yes. Although it’s been appreciated for a number of decades, study of this kind of relationship between climate change causing volcanic eruptions is relatively recent. There’s been a lot of study of how eruptions can affect climate, particularly by throwing ash up into the upper levels of the atmosphere, in the stratosphere, and then reflecting sunlight away, which can cause the Earth’s surface to cool.
Miller: Just so I understand: That’s different from carbon dioxide or other, even more powerful, heat-trapping gasses where the light can go through but then the heat can’t escape? You’re saying that from major volcanic eruptions, they actually prevent the incoming solar radiation, some of it, from heating the earth?
Fink: Right. One of the best examples is the same eruption I mentioned – Mount Pinatubo in the Philippines – which was responsible for lowering the temperature in the Northern Hemisphere for two years. It was a detectable decrease. I was living in Phoenix, Arizona at the time, and the following summer was noticeably cooler than others, especially if you look from a statistical standpoint. There’s sulfur in the magma that erupts, and some of that – the sulfur particles and sulfur gasses – get thrown up into space, and they can reflect sunlight very effectively.
Miller: That’s the kind of natural phenomenon, I think, that would-be geoengineers dream of when they talk about actually decreasing the amount of sunlight that’s hitting the earth, right?
Fink: Exactly. In fact, there was a report out of the White House two days ago talking about this kind of geoengineering – things that we, as society, could do to try to, on a massive scale, interfere with the heating that’s going on from the CO2 buildup that’s happening around the planet.
Miller: We could also burn fewer fossil fuels.
Fink: Exactly. We could do a lot of other things that would be less risky. I had a paper about 10 years ago talking about how one method of geoengineering would be if all the cities in the world did the kinds of things that Portland was doing at the time in terms of trying to encourage more transit use and moving to more renewable forms of energy. That would be a kind of geoengineering that wouldn’t have all of the unintended consequences that we really can’t figure out about putting artificial eruption clouds in the atmosphere or changing the chemical composition of the ocean because it might then be able to absorb more CO2, some of those kinds of things.
Miller: But I had interrupted you as you were talking about what to me is actually the potentially surprising possibility of climate change affecting eruptions. I think of volcanic eruptions as just being about melted rock under the surface of the earth somehow explosively or bubblingly coming up. How is it that a warming world could affect that?
Fink: Well, there are two ways that have been suggested. One is by the melting of glaciers. Glaciers represent a considerable amount of weight that pushes down on volcanoes, like at Mount Rainier or a little smaller amount at Mount Hood. If you remove that weight, then the pressure that the magma body at depth is feeling is reduced, and that might make it easier for an eruption to occur.
Miller: Oh, like if you have your finger on a balloon that has a tiny hole on it, and then you move your finger away?
Fink: Something like that.
Miller: [laughs] Okay.
Fink: Then the flip side of that is, if sea level rises, the volcanoes that are either entirely under the ocean or on islands, like in Hawaii, they might have additional pressure put on the molten rock at depth, which might change the timing of the eruption. It’s not likely to trigger a great increase or great decrease in eruptions. But one of the things that’s key is that volcanic eruptions can be triggered by very slight variations in the environment of the volcano. Sometimes there are things like a big earthquake that happens, which jiggles things up and allows the volcano to erupt. But in many cases there’s a very delicate balance, and slight differences, like from the tides or from rainfall or in this case from melting of glaciers or sea level rise, could be enough to change when a volcano is likely to erupt and the type of eruption that you might get.
Miller: What kinds of advances have there been in terms of the observation and the prediction ability of volcanologists to say, “We think that this volcano is going to erupt at this time?”
Fink: Well, there’s one thing to be aware of which is that, although we hear about eruptions fairly often, there haven’t been that many of them that we have enough information to really understand what causes them to erupt. We have a relatively small number of eruptions that have been observed scientifically in the last 100 years or so, and so we’re still figuring things out and figuring out some pretty major questions like, “Why is this volcano going to erupt when it does? And when might that eruption stop?” Those would seem to be the most obvious things that one would want to know, but we still don’t really have the answers to those kinds of questions.
To your point, what have we learned? We’re collecting more and more information from the volcanoes that are all around the earth, using satellites, using instruments that can be distributed relatively inexpensively, using radio communication to bring those signals back to where they can be studied. So we’re getting a much bigger database of volcanic eruption information, which then informs how we interpret future eruptions.
The other main thing is that, just as the internet has made communication of all types more effective and more widespread, the same is true for studying volcanoes. It used to be that any given volcano would have one or a small number of scientists who would study it. Then they would publish papers, and other people would look at those papers and learn from them and maybe comment on them, on a scale of decades. Now, you can have an eruption starting, and you could get 1000 geologists from around the world and other scientists and policymakers to all be working on that problem at the same time. That really makes a large difference when we’re trying to understand very complicated, interdisciplinary problems that involve not just what the Earth is doing but how society is reacting to it – how things like climate change might be affecting those processes.
Miller: I understand that you finished your Ph.D. in 1979, just a year before Mount Saint Helens erupted. How did that affect the course of your entire career?
Fink: It had a huge impact. When Mount Saint Helens erupted on May 18, 1980, I was visiting my parents in the suburbs of New York. I got a call from a friend at the U.S. Geological Survey saying, “Hey, this thing just happened and you should plan to get out here.” My Ph.D. was about lava domes, which are features that come out after a big explosive eruption. Lava oozes out and can pile up over the vent area, and then sometimes those domes can collapse and generate dangerous pyroclastic flows. I had studied these things with prehistoric examples, and they were saying, “No, this is happening right now, and you should get out here.”
I was at Arizona State University at the time, and I wrote a small grant proposal to the National Science Foundation with a couple of other colleagues. We all went up to Saint Helens about three weeks after the May 18 eruption. Then, over the following six years after the explosions happened, a dome started growing in the crater of Saint Helens. It grew for six years. I had a student who studied that dome with me and with members of the U.S. Geological Survey. We got a number of publications out of it. We learned quite a bit from it.
The other thing that happened was, because that eruption was so visible in the United States, a number of students, geology students, moved into studying volcanoes. So, when I became a professor at ASU, there were a lot more students who were interested in studying with me than would have been the case 10 years earlier. I think, stepping back to this question of, how do we learn about how volcanoes erupt…
Miller: In just 30 seconds.
Fink: Sure. That was the example that showed us how a very distinct eruption like that could teach the entire field around the world about volcanic phenomena.
Miller: Jonathan Fink, thanks very much.
Fink: Thank you, Dave.
Miller: Jonathan Fink is a professor of geology and a volcanologist at Portland State University.
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