May 18, 2020

Mt. St. Helens: 40 Years Later

Posted by Shane Hanlon

Mt. St. Helens eruption on May 18, 1980. Credit: USGS

On May 18, 1980, Mt. St. Helens erupted in Washington state, capping off a series of volcanic events that began on March 27th of that year. The May 18th explosions is credited with causing 57 deaths, >$1 billion in property damage, and forever changed the surrounding landscape.

The eruption created a column of ash that shot into the atmosphere and was deposited in 11 U.S. states, landing as far away as Massachusetts, where 13 year old Seth Moran found his parent’s cars covered it in. That moment was a catalyst that inspired him into the field of volcanology, specifically volcano seismology, and to a career with the USGS. Moran is current the lead scientist at the Cascades Volcano Observatory in Washington state he studies and monitors Cascade volcanoes in Washington and Oregon.

In this episode, Moran chats about his path to becoming a volcanic seismologist, the 1980 Mt. St. Helens eruption, and the monitoring and measures that were put in place following the event.

This episode was produced and mixed by Shane M Hanlon.


Shane Hanlon (00:01):

Hi, Nanci.

Nanci Bompey (00:02):

Hi, Shane.

Shane Hanlon (00:03):

How’s your isolation going?

Nanci Bompey (00:07):

It’s going well, as good as can be. I guess that’s what the … what everyone’s saying. We’re in week what? Eight now?

Shane Hanlon (00:14):

Yeah, it’s just all running together.

Nanci Bompey (00:16):

As we’re talking. So I guess for most people it’s like, “How’s it going?” It’s like, “It’s going,” you know?

Shane Hanlon (00:19):

Yeah. We’re figuring it out. We’re still doing episodes, so that’s nice.

Nanci Bompey (00:23):


Shane Hanlon (00:25):

Well, today, we are talking about natural hazards, and we’ll get into that, but I realized, as we were talking before this, that I guess we’ve been kind of … both of us have been fortunate, that we’ve never really had any major, I guess catastrophes, happen to us.

Nanci Bompey (00:43):

Yeah, we were talking about, like, have you ever been involved with a natural disaster, like a hurricane or a tornado, wild fires? Luckily … earthquakes. I guess, luckily, neither of us have experienced … We’ve all had the snowstorm and the small things, but the really big ones, that’s been fortunate, yeah.

Shane Hanlon (01:00):

Yeah, even like-

Nanci Bompey (01:01):

For both of us.

Shane Hanlon (01:02):

In a very bad thunderstorm, I had a tree fall on a house I was living in, but it didn’t really do a ton of damage. Oh my God, actually, no, this is funny. I totally forgot about this until we were talking about this right now. That was back when I lived in Memphis, Tennessee, but recently, last year, we had this tree fall on our house. It was a week where it just rained. It’s been like this summer. Our neighbor’s tree split and a big part, probably a foot in diameter, slowly, very slowly, over the course of a few days, just came down onto our shared fence, and then very slowly onto our house. The thing is, we rent, and we know our neighbors, but this one neighbor, he’s a recluse, and I mean that clinically. He doesn’t come out. He doesn’t say hi to anyone. So, we went to his house to try to get his attention. He didn’t come out.

Nanci Bompey (02:02):

Oh, wow.

Shane Hanlon (02:03):

We had to go through our property manager to talk to our landlords, who knew him, who ended up calling him. Then, one day, I came home and the tree was just gone.

Nanci Bompey (02:13):

Just magically gone.

Shane Hanlon (02:14):

Just magically disappeared. So, I-

Nanci Bompey (02:17):

Slow motion disaster, I guess.

Shane Hanlon (02:19):

Yeah, yeah, exactly.

Shane Hanlon (02:24):

Welcome to the American Geophysical Unions Podcast, about the scientist and the methods behind the science. These are the stories you won’t read in the manuscripts or hear in a lecture. I’m Shane Hanlon.

Nanci Bompey (02:33):

And I’m Nanci Bompey.

Shane Hanlon (02:35):

And this is Third Pod from the Sun.

Shane Hanlon (02:39):

All right, so we’re talking about natural hazards, natural disasters, and the reason that I brought all this up is that this year, today if you’re listening to it, but May 18th, is the 40th anniversary of the major eruption of Mount St. Helens in Washington. It’s erupted a handful of times since then, but they’ve all been relatively minor. The 1980 one was the big one and it killed 50-some people and it changed the landscape forever. Actually, at our annual meeting this past fall, past December, I had the chance to sit down with someone who knows a little something about Mount St. Helens.

Seth Moran (03:19):

So my name is Seth Moran and I’m right now the scientist in charge of the Cascades Volcano Observatory. I work for the U.S. Geological Survey, which is the government agency that is responsible for issuing volcano hazards assessments and eruption forecasts. My scientific background is I’m a seismologist with a specialization of working with earthquakes that happen in volcanoes.

Shane Hanlon (03:47):

Seth has a pretty epic job. A seismologist who studies earthquakes at volcanoes? That’s a natural hazards double whammy.

Nanci Bompey (04:01):

Yeah, that’s like all the science squeezed in there.

Shane Hanlon (04:01):

It’s like all of science. It’s definitely a bunch of the natural hazards, I’ll give him that, but that’s … I found that so fascinating. That’s so unique. So, naturally, I was interested in how he got into his career.

Seth Moran (04:13):

Yeah, so there’s not many of us that would call ourselves volcano seismologists.

Shane Hanlon (04:17):


Seth Moran (04:17):

It is a little bit of a niche thing. My own path sounds a little bit deceptively linear. I was really interested in volcanoes and earthquakes and dinosaurs as a kid. I lost the dinosaurs but kept the volcanoes and earthquakes. Then, when Mount St. Helens erupted in 1980, the books that I’d been reading up until that point had all talked about the Cascades as being … or volcanoes in the United States, especially the lower 48, as being sleeping giants. Then, all of a sudden, here was this sleeping giant that wasn’t sleeping anymore. A couple days later, there was a little dusting of ash that fell on a car that was parked on my parent’s car in Massachusetts.

Shane Hanlon (05:00):


Seth Moran (05:00):

That, along with the coverage that led up to that, was really fascinating. That really galvanized my interest.

Shane Hanlon (05:09):

If you don’t mind saying, how old were you?

Seth Moran (05:11):


Shane Hanlon (05:11):

  1. Okay. That’s … I didn’t know what I wanted to do when I was 13.

Seth Moran (05:16):

I won’t say that I knew this is what I wanted to do, but it was really something that fascinated me. As one figures out what one wants to do with one’s life, it’s good to pay attention to things that are fascinating and that often tells you something.

Shane Hanlon (05:32):

13 and knowing what you want to do. That blows my mind.

Nanci Bompey (05:38):

I still don’t know what I want to do.

Shane Hanlon (05:41):

So then you definitely didn’t know what you wanted to be when you were 13?

Nanci Bompey (05:45):

Well, as a kid, I always really liked architecture. I feel like I wanted to be an architect at one point.

Shane Hanlon (05:49):


Nanci Bompey (05:49):

Yeah, which I’m kind of sad I never pursued that, to be honest.

Shane Hanlon (05:52):

Interesting. I-

Nanci Bompey (05:54):

Doctor, probably, because I did like science, math.

Shane Hanlon (05:59):

Yeah, I just realized that I had no aspirations. I didn’t want to be anything. I had just never thought about it. I didn’t know that I wanted to be what I am now. Well, now, who knows? But a scientist, even, until I was in college. So 13’s pretty impressive, but from there, we talked about not only how he got to where he was, but then the actual mechanics of what he does. How do you monitor volcanoes on the ground?

Seth Moran (06:27):

So, a lot of it actually should be done without people actually being on the ground because it’s a hazardous kind of thing and there’s some inevitable amount of time you need to spend on the ground, installing instruments, or making measurements with gas. Oftentimes, gas monitoring, you really have to go to the vent where the gas is coming out to get a very precise measurement. Also, with geologic monitoring, if the volcano erupts, the imperative is you want to collect what erupted really fast before rain makes it go away. So there’s things like that, but in Mount St Helens in 1980, one of the challenges there was, it was very difficult to do things like that without people being out there. The technology just wasn’t there. It was one of the first eruptions like Mount St. Helens that was monitored by realtime, seismic network, so seismologists didn’t have to be out there, although they were out there taking fairly significant risks, putting stations on the volcano in the early parts of the crisis for that, but in contrast, there were other kinds of measurements that were being made, like with gas, where, among other things, a scientist named David Johnston was on the volcano a number of times, going into the crater that was forming to collect gases. Then, another part of it was the volcano was deforming. People could see that by eye, but there wasn’t any real easy of measuring that precisely.

Shane Hanlon (07:56):

Can you describe deforming?

Seth Moran (07:57):

Yeah, so deforming just means changing shape.

Shane Hanlon (07:59):


Seth Moran (08:00):

Really, the more captivating word is bulging.

Shane Hanlon (08:04):


Seth Moran (08:04):

There was a flank … north part of the volcano was bulging outwards. People could see that, but there wasn’t really a sense of … nobody had a good way of quantifying that, just because technological limitations were what they were.

Shane Hanlon (08:16):


Seth Moran (08:16):

So people had to go out there. They put some reflector targets up on the volcano and then had to be physically present to be using basically a laser to measure the distance to these different targets. Then, day over day, you check what’s the distance change? That required somebody being out there and it also required good weather and all those other things. They were able to measure rates and they were able to see if the rates were changing, but in the end, one of the scientists who was doing that was caught up in the eruption.

Shane Hanlon (08:48):

So, Nanci, can you imagine putting yourself in danger to get the job done? Have you ever been in a situation where it’s been dangerous for you to do what you needed to do?

Nanci Bompey (09:02):

When I was a reporter, we were probably put in some weird situations and not good situations.

Shane Hanlon (09:06):


Nanci Bompey (09:07):

But one kind of … I wouldn’t say it was life-threatening at all, but I was going up with these people up a mountain to check out this area that they had … a piece of land that they had conserved. So you’re going through … It’s like you’re hiking up a mountain, whatever, and I’m trying to take notes, and we’re crossing the water and I fell in. I fell in a stream.

Shane Hanlon (09:30):

What were you-

Nanci Bompey (09:30):

Got soaking wet.

Shane Hanlon (09:33):


Nanci Bompey (09:33):

But I had my notebook in my hand. I was like … preserved my notes, so that was good.

Shane Hanlon (09:38):

You literally just like were walking across a stream.

Nanci Bompey (09:40):

I fell off a rock.

Shane Hanlon (09:40):

You just-

Nanci Bompey (09:41):

It’s just some rocks in a small stream and I just totally fell in. Yeah.

Shane Hanlon (09:46):

Oh, that’s great.

Nanci Bompey (09:47):


Shane Hanlon (09:47):

Oh man. I’m picturing this in my mind. It makes me so happy.

Nanci Bompey (09:51):

Yeah. Not life-threatening, but …

Shane Hanlon (09:54):

Not life-threatening, sure. Well, so from there, we ended up talking about the actual timeline of Mount St. Helens because what … I think I didn’t quite realize that the eruption was on the 18th, but things were set in motion literally months before then.

Seth Moran (10:11):

It was a pretty compressed timeline when you think back on it, but the first earthquake that caught people’s attention was on March 20th. It was a magnitude 4.2. It was broadly recorded across a pretty recently installed network around the state of Washington. Fortunately, one of those stations was right next to Mount St. Helens. The earthquake itself was located with some error because there were not that many stations nearby, and so there was uncertainty in the location of about five kilometers, which allowed an interpretation of it was either volcanic or it was on a nearby tectonic fault. It took a day or two to see what was happening with the earthquakes, which started increasing in time, as opposed to decreasing, which is what you’d see with an aftershock sequence. So at that point, people knew what they were dealing with and pretty much right away started trying to install stations.

Seth Moran (11:14):

It was just seven days after that first earthquake when the first explosion came out of the surface, at the top. So that was a pretty compressed timescale. Then, over the course of the next couple of weeks, through overflights and other ways of monitoring the volcano, people were noticing that the crater was broadening. Then, at some point, started noticing that the north flank looked different than it had before. You think back to then, one of the ways that you could document that with photography, but back then, you took a photo and then you had to go off to some place to get it developed.

Shane Hanlon (11:51):

There was no digital.

Seth Moran (11:52):

You get it developed and then one of the things that we do today, very commonly, is you set up time lapse cameras and then you can just flip back and forth in like a PowerPoint or a QuickTime video or something like that, but how do you do that with a slide deck? Ca-chink. Pull it. Ca-chink. Also, how do you send that to other colleagues who aren’t physically present with you? Making copies and sending them around. So, it was really hard to document in a way that enabled you to constrain what was happening and have it be done fast and have it be done in a way that could be broadly transmitted. Now, it would be instant.

Shane Hanlon (12:25):


Seth Moran (12:26):

We’d have webcams out there. We’d have GPS instruments on the volcano. We would know, as would the rest of the world, because we put that data on the web in real time. So, pretty much anybody can see what’s going on, but back then it took days, if not weeks, to get the processes completed that would give you a definitive answer for what was happening.

Shane Hanlon (12:44):

Were they trying to do that? Or you just couldn’t? Everything happened so fast that they were seeing these visual observations, but they couldn’t then quantify it because of the technology?

Seth Moran (12:54):

That’s where this electronic distance measuring, putting targets up on the volcano, that started happening in early April. Another really complicating factor is that early springtime is not the time to be trying to do something like this in the Cascades. Anybody who’s been out there, as you have, in April, you know there’s a lot of snow.

Shane Hanlon (13:12):

There is.

Seth Moran (13:12):

And the weather is not great. A lot of this was helicopter-access required. There were numbers of days where they just couldn’t do it. So, there were a number of challenges that they faced in establishing a monitoring network and getting the kind of information they needed to do the job of monitoring the volcano.

Shane Hanlon (13:33):

So, the first earthquake was March 20th. They began installing these monitoring stations, these relay points, throughout the month of April, and then the eruption is in May, correct? May 8th?

Seth Moran (13:46):

May 18th.

Shane Hanlon (13:46):

May 18th. Okay, thank you. How well do they know, or could they guess, that it was going to be around then? What was the prediction at that point? How accurate was that? What kind of was the attitudes of folks, not only the scientists, but the people in the area, leading up to it while all this is going on?

Seth Moran (14:03):

Right. From the monitoring perspective, the first week, things ramped up. When things ramp up, it’s relatively easy to get people’s attention and to feel like something’s actually going to happen. After that first explosion, a lot of the monitoring indicators kind of leveled off, so with the [seismicitiy 00:14:25], the rate of earthquake occurrence ramped up until you got to that first explosion, and then it kind of leveled off and actually even declined a little bit. The energy released by those earthquakes also kind of leveled off. So, from those indicators, there wasn’t anything that seemed to be building. The first explosion ushered in a period of time where there were explosions daily, and people were trying to find places where they could go watch these explosions, but as you got into the month of May, they started dying off.

Seth Moran (14:56):

It was getting to the point where there was a fair amount of pressure coming back on the forest service because they put out land use restrictions, they’d put out exclusion zones and things like that. The exclusion zones, at that point, included summer cabins that people had on Spirit Lake and were leasing the land from the forest service. The forest service was saying, “No, no, no, no, you can’t go there.” There was a lot of pressure on that. Also, there was pressure from logging companies to be allowed to come in. In fact, if you look at the exclusion zone that had been put in place from late April up until May 18th, it’s not this nice, round, even distance on all sides. It was pretty close on the west side to the volcano, and that reflects where logging companies have exerted pressure to be allowed to work in fairly close distances. Some of the people that were caught up in the eruption were logging folks. It would have been a lot worse, except that the company loggers, for Warehouser and other groups, were … It was a Sunday, so they were off.

Shane Hanlon (16:06):


Seth Moran (16:07):

But there were contracting loggers who were still out there working. There’s a really very fraught story involving these cabin owners on Spirit Lake, that they had exerted so much pressure that they let one of the county sheriffs, who was responsible for staffing a roadblock, know that they were going to come on May 17th and they were going to go visit their houses.

Shane Hanlon (16:33):

Oh wow.

Seth Moran (16:34):

They brought some implements to ensure that they would be able to get through the roadblock. So the county sheriff met them and he had them all sign a waiver that said “I recognize that I’m putting my life in … ” I’m paraphrasing, but-

Shane Hanlon (16:47):

Of course, yeah.

Seth Moran (16:47):

“[crosstalk 00:16:47] your life in danger, and I absolve you of any responsibility” and then they all went in.

Shane Hanlon (16:52):

How many are we talking? Do you know?

Seth Moran (16:55):


Shane Hanlon (16:56):


Seth Moran (16:56):

Yeah. I don’t have an exact number.

Shane Hanlon (16:58):


Seth Moran (17:00):

They were escorted by the sheriff. It was a nice day and people were kind of hanging out. Towards the end of the day, the sheriff was like, “Okay, it’s time to go.” A couple people were saying, “Hey, maybe I could stay here for the night” and he’s like, “No, no, no, you have to go.” So they all left. The next morning, there was another group of home leasers that were queued up to come in. They were going to go in, something like 9:00 in the morning, 10:00 in the morning, when the eruption happened at 8:32.

Shane Hanlon (17:28):

Oh wow.

Seth Moran (17:29):

So just shift that timing 12 hours either way and the fatalities would have been a lot, lot bigger, and there would have been all kinds of questions about, “Well, what was the county sheriff doing letting these people in?”

Shane Hanlon (17:39):

That’s wild that the difference of, what? Like an hour and a half, saved tens, if not hundreds of lives because they weren’t in there. It’s interesting about the timing of these things, and potentially maybe warning times.

Nanci Bompey (17:55):

Yeah, how much warning do you even get before something’s about to erupt?

Seth Moran (18:00):

It varies from volcano to volcano as far as how much warning you get. There’s no magic recipe. Some volcanoes you get months or years of warning, and other volcanoes you literally get hours.

Shane Hanlon (18:12):

Oh wow.

Seth Moran (18:18):

It’s something that our community is grappling with and trying to understand what’s the rationale? What’s the … Are there systematics that we can work with to understand which parts of a volcano is going to give us that kind of warning? When I said compressed, I was partly talking about the first week.

Shane Hanlon (18:36):

Okay. Sure.

Seth Moran (18:37):

But also, that a month and a half between … well, actually two months, between March 29th and May 18th, turned out really not to be enough time for the whole response system to be ready for what happened on May 18th. So there was all this negotiation about the restriction zone and it changed two times. It was going to change a third time the next day after May 18th. It was going to go back out to be a little bit more restrictive.

Shane Hanlon (19:08):


Seth Moran (19:09):

So there was all this tug and pulling and pushing that was happening at fairly high levels. That reflected that nobody had really dealt with anything like this before. One of the things that’s on our plate now, in the 21st century, is to ensure that the lessons that were learned and the stories that came out of 1980 continue to be in people’s minds, so that the next time we get something erupting on our turf, in the Cascades of Washington and Oregon, that it’ll hopefully be a little bit less fraught on that front.

Shane Hanlon (19:48):

Yeah, so that’s actually … So we got up to the days leading up and the actual eruption. That’s what I’m interested in is kind of who’s the pressure being exerted upon? Who was that, ultimately making these decisions about the exclusion zone and that type of thing? You mentioned local law enforcement, that was one thing, but it seems like there was probably scientific and federal agencies and whoever else. How did that interplay work? Is that interplay different now?

Seth Moran (20:18):

Yeah. So, back then, it was the forest service primarily, because they own most of the volcano, although, ironically, Burlington Northern owned the summit.

Shane Hanlon (20:29):

Is that the forest company?

Seth Moran (20:30):

That’s a train company, a railroad company.

Shane Hanlon (20:32):

Oh, of course. Northern owned the summit?

Seth Moran (20:33):

Yeah. So-

Shane Hanlon (20:37):

How does that work?

Seth Moran (20:38):

That was … there were land trades that were happening all over the place and that’s what happened.

Shane Hanlon (20:42):

Oh, okay.

Seth Moran (20:42):

So, although the forest service could close the volcano, they couldn’t close the summit, and so there were media companies that were landing on the summit and there was nothing the forest service could do about it.

Shane Hanlon (20:51):

Oh goodness.

Seth Moran (20:51):

That wouldn’t happen today, but it was … the land management agencies, and in combination with local and county and state officials, that were making the decisions about where the lines were. In this case, it was the governor that was making sort of a final sign-off on exclusion zones. That was because there was a mix of private and public lands and it just needed to have one person who was making the final decision. So it was pretty chaotic. There have been other emergency crises, not volcanic, that have happened since then. In California, there was the Oakland Hills fire, that the response there was chaotic enough that that motivated the development of something called the Instant Command System.

Shane Hanlon (21:44):


Seth Moran (21:45):

That is now something that is codified by FEMA and is used around the United States for organizing responses, because any time you bring multiple agencies into it, it can get pretty complicated, so there’s this one system that people understand. Things can change from incident to incident, but that would be the agency … not agency, but the …

Shane Hanlon (22:11):

The plan? The governing plan or whatever?

Seth Moran (22:13):

The group.

Shane Hanlon (22:14):


Seth Moran (22:14):

That would oversee the responses and decisions about things like, what is the exclusion zone?

Shane Hanlon (22:22):

I was genuinely shocked when he told me what Burlington Northern was, that it was a railroad company, and that they owned a volcano. Nanci, what would you do if you owned a volcano?

Nanci Bompey (22:33):

Huh. That is very … if I owned a volcano? I don’t even know. What would you do if you owned a volcano? I’d be scared of it.

Shane Hanlon (22:43):

Yeah, I know. I don’t-

Nanci Bompey (22:44):

I’d be scared it was going to erupt.

Shane Hanlon (22:46):

I don’t know if I would ever go anywhere near it, frankly.

Nanci Bompey (22:48):


Shane Hanlon (22:49):

That’s not true. I’d talk to one of our good members who know something about this, maybe go see it, but yeah, I have no idea. What do you do with a volcano?

Nanci Bompey (22:57):


Shane Hanlon (22:58):

But from all of this, there definitely were some lessons learned, for better or for worse.

Seth Moran (23:09):

One of the lessons that came out of 1980 is that you really want to try and avoid having a volcano wake up on you without having at least a basic level of monitoring capability on it.

Shane Hanlon (23:21):


Seth Moran (23:22):

Because you take risks, you miss stuff, there’s uncertainties in the interpretations you make because you don’t have really good information about what just happened. So, like that earthquake that started everything off, there was this uncertainty about, was it volcanic or tectonic? You don’t want to have that uncertainty. That puts you behind the eight ball right away. So that’s a push that we’re actively engaged in right now in other volcanoes in the Cascades, and actually, around the United States, that volcanoes that are deemed to be of highest priority, sort of are posing the most threat to people, either because they erupt frequently or a lot of people are close to them. Those are volcanoes that we need to be trying to get networks in place that are kind of like what we have at St. Helens.

Seth Moran (24:06):

We’re making some progress, but there’s a lot of turf to cover. It’s really incumbent upon us to produce products that are intelligible and do a good job of communicating our understanding of the hazards to people in different ways. Primarily, we do that through interacting with local communities, with stakeholder working groups. Occasionally, we have public forums, and we have products that go up on the websites and things like that. So, our goal is to have it be easy for people to get the information, but there’s nothing that’s forcing anybody to read that and there’s … certainly if somebody buys a home, there’s nothing that forcing realtors to tell people “You’re in a [inaudible 00:24:48] hazard zone.” So, it’s a balance.

Shane Hanlon (24:54):

Well, Nanci, what would you say, then, the moral of the story? Not the whole story, at least the last part here, what Seth was talking about?

Nanci Bompey (25:04):

Don’t buy a house near a volcano.

Shane Hanlon (25:05):

Oh, yeah.

Nanci Bompey (25:07):


Shane Hanlon (25:08):

That’s probably a good one. I feel like, back to our original discussion about the natural hazards we have or haven’t experienced, it’s one thing to be somewhere cold or be somewhere in a flood plain, but I feel like not being near a volcano is a pretty easy task.

Nanci Bompey (25:24):

Yeah. It’s out there. You kind of can see it.

Shane Hanlon (25:28):

Right. All right, folks. Well, that’s all for the Third Pod from the Sun.

Nanci Bompey (25:32):

Thanks so much, Shane, for bringing us this story, and thanks to Seth for sharing his work with us.

Shane Hanlon (25:37):

This podcast was produced and mixed by me.

Nanci Bompey (25:41):

And we’d love to hear your thoughts. Please rate and review us on Apple Podcasts, and you can find us wherever you get your podcasts, or at

Shane Hanlon (25:51):

Thanks, all, and we’ll see you next time.