40 years ago this month, Mt. St. Helens erupted. We are volcano scientists. Ask us anything!

I was on a geology field trip in Oregon in the John day area when Mount Saint Helens erupted. I had just gotten back onto the bus and didn’t hear it but other students came piling under the bus and said, “Did you hear that?“

We all got back out of the bus and saw three geology professors hop into the state pick up truck and drove off without us. It was completely understandable.

The bus went north toward the Columbia River and then turned and went west along the gorge. We could see the huge plume which appeared to be stationary because it was so huge yet we knew that there was turmoil inside.

WooHoo!! MentalFloss1, you're in the small club of eruption eyewitnesses. Which one was it? May 18, 1980?

Was there something in particular that was learned from the St. Helen’s eruption that helped further our understanding of volcanoes or seismic activity? 🌋

This is Alexa. Something we don't talk about very much, but has had tangible downstream effects on the science, is that the 1980 eruption produced a ton volcanic lightning and thunder. Eyewitness observers have mentioned it time and time again - lightning was also caught on camera and video. The interesting thing about this is that one of the lead geologists at the time, Rick Hoblitt, noticed that the flash rates changed when there was a vertical plume compared to ground-hugging pyroclastic flows. And it dawned on him that lightning could be used to remotely track changes in eruption style. 40 years on, we're still at the early stages of impelmenting some of those ideas.

Especially in the 1980-1986 dome forming phases, there were many eruptive cycles where scientists could test hypothesis and gather observations. We learned a lot about low and high frequency earthquakes and monitoring deformation. Many successful forecasts were issued during that time. --Wes

When do ya’ll think Rainer is gonna blow?

Until there is some sign of reawakening--by unusual and prolonged earthquake activity, or unusual gas release, or deformation, we won't be able to assess when magma is rising beneath Mount Rainier moving us into eruption. Right now, Mount Rainier shows no signs of reawakening, but it shall in time--perhaps in our lifetimes, or maybe thousands of years from now. The important thing is to keep the volcano well monitored and for authorities and communities to be prepared.

Thank you. But my next question is how the hell do you prepare for that? Years ago I read that the mudslide could make it all the way to the ocean. We can’t evacuate that densely of a populated area. If we knew it was going to blow, how many people could we actually save? Percentage wise. How much warning could we get? Would it be like hey this thing could blow at any moment up to 2 years? What would that estimate look like? Thank you! Fascinating to hear from you. Y’all rock!

This is Mike. Mudflows are fast, but with warning, it is possible to get out of the way. Just like a hurricane, the best mitigation strategy for a volcano is not to be in the path of any destructive flows. The Cascades Volcano Observatory is working with WA EMD to develop a new lahar warning system that would provide advance notice of destructive lahars before they reached impacted areas (not every place is impacted...just areas in drainages, so you don't have to evacuate everyone). The idea is to provide critical minutes so that people can get uphill and out of hazard zones. This has even been the subject of drills in the town of Orting, WA, which was built on Rainier lahar deposits.

Follow up question, same but Mt. Baker.

As with Mount Rainier, no signs exist of imminent reawakening at Mount Baker. Recall that heightened thermal steam activity in 1975 caught the attention of everyone, but it did not lead to an eruption. Again, monitoring is important at Mount Baker, as is the constant attention of scientists and authorities.

Can I add Yellowstone super volcano to the list? And what qualifies as a super-volcano anyway?

This is Mike. No signs that Yellowstone is going to erupt anytime soon (as in, within thousands of years). The magma chamber is mostly solid! As for "super volcano," I really hate that term (you can read why at https://www.usgs.gov/center-news/a-personal-commentary-why-i-dislike-term-supervolcano-and-what-we-should-be-saying ). But the phrase is meant to apply to volcanoes that have had eruptions exceeding 1000 km3 in volume. Those are super eruptions. I don't mind that term. But "super volcano" is something I don't say unless I'm talking about why I won't say it.

Is Liz Westby the one running the USGS volcanoes twitter account? Whoever it is-- thank you SO MUCH! Your work to shine a light on the ramp up to May 18, 1980 with Mt St Helens has been phenomenal!

Glad you like it! I'll give you the inside scoop for Monday May 18 - I have 21 posts that will go up throughout the day with updates about events unfolding at the volcano in 1980. Doing both USGS Volcanoes Facebook and USGS Volcanoes Twitter - your choice. - Liz

This is Mike. Yes, we are all in awe of Liz's daily MSH retrospective posts! She's amazing!!!

Wendy here - yes...we've decided that Liz has a super hero capability when it comes to communicating Mount St. Helens!!

Volcano or Dante's Peak?

This is Mike. Dante's Peak, totally. When this movie came out, I happened to be home from college. My Mom, when I told her Pierce Brosnan was going to be in a volcano move, remarked, "Pierce Brosnan can check out my volcano anytime." Without looking up, my Dad said, "He'd find out it was extinct."

Is a phreato-magmatic steam eruption documented from the head of your mom after?

She laughed. I'm scarred for life, though.

Dante's Peak! It's much more realistic...but also in the Cascades (winning). Not to mention, snorkels on vehicles are clearly necessary for traversing lava flows. - Wendy

Plus the heroes are USGS employees! Might be the only film that's ever done that.

Totally. AND they're wearing Cascades Volcano Observatory t-shirts in the movie...which are more or less the same ones we wear nowadays. -Alexa

Dante's Peak all the way. -Alexa

Yellowstone..... what’s the deal with that?

This is Mike. The deal with Yellowstone is that it's awesome!!! A beautiful place, and a wonderland for studying all kinds of volcanic processes, from the largest eruptions on the planet (the big caldera-forming ones, most recent 631,000 years ago) to the smallest (tiny steam explosions which happen pretty frequently). But maybe you're wondering about current activity? It's pretty normal (which is to say, lots of geysers erupting, 1500-2000 quakes per year, and the ground moving up and down a rates of up to a couple of inches per year -- that's Yellowstone being Yellowstone). Lots of people online -- tabloids and random "experts" -- like to make up things about Yellowstone for attention. Too bad, since the place is plenty spectacular without having to resort to making things up!

So it's not going to go big this year? I mean, it is 2020

This is Mike. Nope! There's enough to worry about in 2020...

Hi All, this is a really cool AMA you're all collectively hosting! Fellow geologist here with a couple questions on volcanic lightning. What needs to happen during an eruption to produce volcanic lightning? Is there any correlation between the style of eruption and probability of lightning occurring?

We're happy to be here. This is Alexa. Volcanic lightning is a pretty new field of study, so there's a lot we still don't know. But so far we've been able to observe that volcanic lightning develops whenever you have an ashy, vigorous plume. If there's no ash, there's no lightning. Very small steam plumes in Iceland (Surtsey) and Italy (Stromboli) can carry an electric charge, but don't actually produce flashes of lightning because they don't contain ash particles to kickstart the charging process. There are definitely relationships between eruption style and lightning flash rate. Two things worth mentioning there: (1) we've observed an on/off effect where plumes don't produce globally-detected lightning until they rise into freezing level of the atmosphere (typically 5-10 km), and (2) once ice-charging gets going inside a volcanic plume, the lightning flash-rate increases with plume height. So it's a potentially useful indicator of aviation-relevant ash hazards at high altitude.

What made you decide volcanology was the right field for you? And what academic path did you take to get into volcano science?

Hi there. Everyone has a slightly different story about how they got into volcanology, but for me it was the combination of outdoor exploration and lab analysis - and getting a chance to learn how to read the layers of the earth like a book. -Alexa

What did you study inorder to now be working as a volcanologist?

Larry here. Most of us geologists studied geology. But there are also hydrologists, chemists, geophysicists, cartographers, electronic specialists, and even a few social scientists who study how people react to warnings about possible eruptive activity. I'm a geologist. But the guys who get to ride in the helicopters most often are the electornics geeks, because they're always changing out batteries for the seismometers.

That's cool, do any geographers/ natural hazard managers get to do that kind of stuff?

This is Mike. Absolutely! For example, at the Cascades Volcano Observatory GIS experts work with volcanologists to design hazards calculation tools -- like how to determine the areas that will be impacted by lahars of various sizes on different volcanoes. These tools can then be used by emergency managers in community awareness efforts.

Just a constant fascination of looking around at the mountains and other landforms around me and wondering "Huh... Why does that look like that?" And then in Summer 2004, i got to Climb Mt. St. Helens (about a month before it's eruption started), and just became completely fascinated with volcanoes. Became fascinated with them, studied geology in college, then asked all my contacts possible who I would need to study with to study active volcanoes, and ended up studying volcano geophysical volcanology.Switched to Emergency Management (but absolutely needed to be related to volcanoes) in order to take what I'd learned and experienced, and apply it towards mitigating those hazards!
Definitely an interesting public service aspect to it, but a path where you don't necessarily wind up doing much research.
- Brian

When the big 9.0 hits off of wa coast will baker or helens erupt?

The last time that the Cascadia Subduction Zone had a major earthquake, In January 1700, none of our Cascades range Volcanoes erupted. We can also look at other Subduction Zone earthquakes around the world, like the Andaman Islands in 2004, and the Great Eastern Japan Earthquake in 2011 also did not seem to cause any volcanic eruptions. (...Personally, I think this is a good sign!)

There are some links between earthquakes and volcanoes, but for the most part, a volcano needs to be almost ready to erupt, with magma near the surface for an earthquake to start the eruption.
-Brian

Oh, hey, names I recognize! To Andy and Carolyn, The Bagwan says hi, and wants you to know he's currently working on his memoirs of his time at CVO. Say hello to Bigfoot and Tom Murray's shirt when you get the chance.

As for a question, there is a lot of misinformation out there on how badly a "big one" on the Cascadia Subduction zone would effect the major metropolitan areas of Portland and Seattle. Could you go into what the actual felt effects would be like?

(Maybe someone else can speak to the inside knowledge there!)

There Is a lot of misinformation about the Big Once, but it would definitely be a dramatic event that would radically change Cascadia, and interrupt the way we do things in the Pacific Northwest. Just looking at Japan after the 2011 Great Eastern Japan earthquake and tsunami, many coastal communities still have not recovered from that event - most tsunami models for a Cascadia Earthquake have tsunamis reaching Seattle - while the waves are much smaller than on the coast by the time they reach that far inland, they still bring strong currents that can drag docks and ships around, and cause millions of dollars to our shipping routes. Models are struggling to show how far up the Columbia and Willamette River will be at the moment.

But the Earthquakes themselves will impact these areas immensely. The shaking will vary across the cities, because different types of sediment amplify or dampen the shaking. Low lying areas especially in river valleys are usually more susceptible to this shaking... so actual shaking damage varies significantly across the metro areas.

However, the things we need to think about with these impacts, is not just the shaking itself, (including thousands of strong aftershocks for months) but the damage that will be done to critical infrastructure (water, wastewater, power, transportation, communications, etc.) Which will take a really long time to repair, and why we really really really need people to prepare for this event. It will be challenging for first responders to ...respond, so you and your neighbors will be the first people to respond. If you think 'right now' with COVID-19 is challenging (which is is), try it without power, internet, or even clean, running water.

Then there are the issues of supply chains, long-term economic damage, etc.;

Yup. It will absolutely be catastrophic. But being aware of that, WA and Oregon are working to Mitigate the impacts that this disaster will have, such as strengthening bridges, helping people understand their need to prepare, retrofitting old school buildings, and building tsunami evacuation shelters, among others. There is still a lot of work to do, but we're making it "less-bad" with every action we take!
-Brian

I live in Orting, WA. How much time will we have to evacuate if Mt. Rainier erupts? What sort of preparedness do you recommend?

The speed of a lahar depends on its size, so it is a little difficult to give a precise answer. For the Electron Mudflow that happened ~1500 A.D., modeling results indicate that a similar-sized event would take ~1 hour to reach Orting. One good way to be prepared is to understand where you live relative to Mount Rainier hazard zones to see if where you live could be impacted by a lahar (or, for that matter, a large flood from the Puyallup River). The USGS CVO has a published simplified hazard map that can be found at https://volcanoes.usgs.gov/volcanoes/mount_rainier/hazard_summary.html . In addition, the USGS is working with colleagues at WA EMD, Pierce County, and South Sound 911 to upgrade a lahar detection and alarm system first installed in the 1990s that is designed to provide alerts to people in the Orting area and elsewhere along the Puyallup River if a large lahar is detected with potential to reach Orting. Any alerts would be issued by WA EMD and South Sound 911, with the alerts sent out in a variety of ways including sirens that are placed throughout the Puyallup River valley. A last thing would be to know what to do if a lahar alert comes out -- what would be the quickest evacuation route, how would you move yourself (ideally not by car, as the roads would likely be jammed) -- Seth

Excellent guidance from Seth! The only thing I would add is getting a Go-Bag ready, with things you would need in case you had to evacuate quickly in case of a lahar. Some tips on what to put in a go-bag and how to get started can be found at https://mil.wa.gov/preparedness.
It's scary to think about, but Orting's annual drills show that even the students (inculding Kindergartners in recent years) are all able to walk to safety within that hour, so that's a really good sign for everyone in the community! Like Seth said, please walk though, to keep those roads open for people in the community who are unable to!

Pierce County has an excellent, informative web page on the hazards specific to your area, and what you can do about them here: https://www.piercecountywa.org/3730/Mount-Rainier-Active-Volcano

-Brian

Was literally searching this up two days ago cause it was so interesting. How common are lateral blasts?

This is Alexa. The May 18, 1980, eruption helped us realize that lateral blasts are much more common than previously thought. Another volcano that shows similar behavior is Bezymianny in Kamchatka, Russia.

Have you ever used a hot spring or fumarole to cook with? If so, what did you cook, and how did it taste?

This is Larry. I have never cooked on a hot spring or fumarole, but I've eaten food that was cooked in fumarolic hot ground in the Azores. Tour operators on Sao Miguel Island cook food for their groups by burying it in a giant pot in hot ground in the crater of Fogo volcano. Then they take it all to a restaurant. It was awesome! The the area has very low sulfur or other gases, so I think it works there.

This is Carolyn. While that is true roasting marshmallows over vents full of rising gases laden with heavy metals is a poor idea.

I have noticed an influx of YouTube channels, journalists and others who are misinformed about Yellowstone and fear-monger an impending or “over due” eruption. Michael Poland does an amazing job with his monthly video updates, however it seems like there is still quite a bit of misinformation out there. What can we do to prevent this and really get the message across that Yellowstone is not overdue or going to blow tomorrow?

Also people seem convinced the recent earthquakes in Salt Lake City and challis, Idaho are connected to Yellowstone in some way. What evidence can we show them to prove they are not?

This is Mike. Glad you like the video updates! That's something I've been trying as a counter to some of the YouTube misinformation, since YVO wasn't really using YouTube much before. But it's a never-ending battle, and my only real strategy is persistence and education. And to answer questions, as much as possible. You're definitely right about the quakes being misinterpreted. I think there, history is a nice guide. Some people act as if there has never been a M6 in Idaho before, for example. They are shocked to learn there there was an M6.9 in central Idaho in 1983. And a M7.3 in 1959 just outside Yellowstone! So, education. Hopefully the memory of these events will last (at least for a few years), and people will realize that these really were tectonic quakes and their aftershocks. But to the extent that those in the know can band together and put out good information, perhaps the good information can win out over the bad. Most people are just looking for information, and don't know who to believe -- they are asking honest questions. So I think it's important that the good information is out there, front and center, to be discovered. Regardless, a full-time job...

From my 9 year old- Can volcanoes erupt under water?

Yes! In fact, keep your eyes peeled to the south of the Island of Hawaii where Loihi is currently having a very vigorous swarm of earthquakes. An eruption, if it occurs, would only be known about the next time there is a remotely-operated vehicle or new survey of the ocean floor.

​

https://volcanoes.usgs.gov/observatories/hvo/hvo_earthquakes.html

​

--Wes

With increased earthquake activity around the Yellowstone Caldera, what is the probability that it could blow in our lifetime?

This is Mike. There actually isn't increased activity around Yellowstone. You might be referring to the M5.7 near Salt Lake City on March 18, and the M6.5 in central Idaho on March 31? And all of the associated aftershocks? Those are tectonic quakes associated with extension of the western USA (we wrote one of our "Yellowstone Caldera Chronicles" articles on that activity a few weeks ago -- https://www.usgs.gov/center-news/whats-all-these-earthquakes-and-will-they-affect-yellowstone). Those quakes aren't related to Yellowstone. Seismicity associated with Yellowstone itself remains at normal background levels -- which is to say, about 1500-2000 quakes per year. The latest Yellowstone Volcano Observatory video update, which also covers the aftershocks of these March tectonic main shocks, is at https://www.youtube.com/watch?v=4MeVcPuRO50&t=3s if you'd like more info. The odds of a Yellowstone eruption in our lifetime are vanishingly small. And remember, most Yellowstone eruptions are lava flows, not explosions. The last lava flow eruption was 70,000 years ago, and there have been a couple dozen of those since the last big explosion 631,000 years ago.

Do you think Te' Ka knew they were really Te' Fiti the whole time?

Yes. I think so! Te'Ka was angry about her heart being stolen! - Wendy

I'm going to confidently parade this answer around, as you are my proof. Thank you!

You're welcome! Best Disney movie ever! - Wendy

What's your personal favorite factoid about the 1980 Mount St. Helen's eruption and the events surrounding it?

This is probably a bit weird, but the week before the May 18, 1980 eruption, USGS scientists asked the National Guard for mobile bunkers to protect scientists while they were on duty at the Coldwater II observation post. The bunkers were supposed to arrive the afternoon of May 18. - Liz

It's grim, but every summer when I'm on the Pumice Plain for fieldwork, I think about how Harry Truman and his 16 cats are buried beneath the debris avalanche deposits. -Alexa

This is Seth - It's hard to pick one, or even 10 or a hundred. For one, it is amazing how much destruction and change occurred during just the first 10 minutes of the eruption.

Can a volcano ever just appear in a region? I’m in Maine And we learned the last eruption in Maine was 420 million years ago and was on the scale of a super volcano.

Is it possible for a new volcano to just show up one day? Or do volcanos only exist near subduction zones?

This is Alexa. Volcanoes only really show up at subduction zones, rifts, and hot spots, and Maine hasn't been in any of those categories for millions of years. So you're safe for now! But when you do lived in a volcanically active region, it is possible for new eruptive centers to pop up. Check out Paricutin in Mexico, which developed in a corn field in 1943.

Could you talk a little bit about becoming a volcanologist or geologist working with volcanoes? It seems like an incredible career path. I’m a geology major in college and would love to get some good advice on how to proceed from here! Thank you all for the AMA!

Hi, this is Alexa. USGS has put together a summary on this topic: https://volcanoes.usgs.gov/observatories/cvo/volcanologists.html. Long story short, it depends which aspect you'd like to get into - instrumentation design, research, or science support. If you give us something more specific we'll be happy to give you some more detailed pointers.

I have 2 questions! I'm a Pacific Northwesterner with an Environmental History degree so super psyched about this ama, thanks for doing this.

1. How prepared does the PNW seem (both cities like Seattle and Portland and rural areas) for another major eruption?
2. Did any unexpected environmental history revelations come out of the 1980 Mt. St. Helens eruption?

This is Alexa. We're happy to be here! There were several unexpected revelations that came out of the 1980 eruption. Just to list two good ones: (1) it revealed that lateral blasts are a more common eruptive hazard than previously recognized in the geological record, and (2) despite drastic transformation and alternation of the surrounding ecosystem, the biosphere bounced back much more quickly than expected. Entire dedicated fields of research emerged from just these two topics, inspired and underpinned in large part by the 1980 eruption.

Hi CoffeeandSoymilk~
For question 1., it definitely depends where you are. Some communities like Orting and Puyallup in Mt. Rainier's lahar hazard zones practice evacuation drills from their schools annually, to prepare students (and yes, they can ALL evacuate in the time needed!
Some other communities have more work to do, but we're all working on increasing hazard awareness. Probably the most important thing that people who live in volcanic hazard zones need to learn, is what they need to watch out for (lahars? Ash?), where they will get information about impending hazards when they need it, and how to avoid those hazardous events when they occur!
Seattle and Portland are not very exposed to volcanic hazards, as they are not actually within any lahar hazard zones, aren't close enough to the volcanoes to be in danger of lava flows, pyroclastic flows or ballistics, and since they are West of the volcanoes, it's much less likely that volcanic ash will fall on them in the event of an eruption. Hope this is good news!
-Brian

(and it sounds like Alexa will help with Part 2!)

Thank you to everyone who is participating in this — as an earth sciences junkie, it's so great to have you here! I'm going to get greedy and put in a few questions.

• Brian: So much has changed since 1980 in terms of how disasters are handled by state and local govt. Knowing some peaks are more impactful than others, can you highlight some of the ways WA EMD is prepared to handle the next big volcanic event?
• What emerging technologies could help unlock some of the Cascades' biggest mysteries (like the mapping of St. Helens's volcanic conduit)?
• Finally, what is it about Mount St. Helens that, 40 years later, still stirs the imagination of so many?

Thanks again!

Hi MrDeene!
For your first question, probably the biggest thing we've realized how important it is to share information and situational awareness between the scientists, responders, local officials, and the media, to ensure that people transparently get the information they need before and after the eruption, and understand that exclusion zones are closed for their protection.
Also, a huge thing we've learned from Mt. St. Helens, is just how long the impacts from lahars can last - a whole sediment retention structure had to be built to prevent ash and volcanic material from dumping downriver into the Columbia River and blocking shipping channels - and there's the whole Spirit Lake tunnel situation, which is a still a problem and potential hazard of the eruption 40 years later: https://www.seattletimes.com/seattle-news/aging-tunnel-near-mount-st-helens-needs-work-to-avert-flood-risks-to-nearby-residents/

and I think it still stirs the imagination for so many 40 years ago, because it was such a dramatic eruption of such an iconic mountain. Everyone who was here at the time has stories about it, and going to Spirit Lake in the shadow of the mountain was a big summer activity for many. Mt. Rainier/"The Mountain" is also so iconic - could you imagine if it erupted and dramatically changed it's shape? ( I personally can't, but Rainier has had eruptions with similarly large landslides that re-shaped it in the past)
-Brian

I'll take on the conduit question. We are finding all kinds of new ways to use existing data and taking advantage of newly sensitive instrumentation. For example, using seismic noise is becoming commonplace now. We are also using gravimeters and deformation together to understand the subsurface better. --Wes

This is Alexa. It's a good question - how Mount St Helens still manages to stir our imagination after 40 years. Did you happen to catch the 40th anniversary exhibition at the Portland Art Museum? https://portlandartmuseum.org/exhibitions/volcano/ The exhibit is still there, but obviously shutdown due to the coronavirus right now. Some of the artwork is archived online. Somehow, seeing the art inspired by this eruption over the years really drives home how influential the eruption has been for people living in the Pacific Northwest and beyond.

Are there any volcano proof shelters? We always hear about tornado, hurricane, and even earthquake proof buildings, but is there an equivalent shelter that can withstand an eruption?

Wendy here.

Well...not really. There have been some attempts, and unfortunately, there have been failures with people dying inside structures during eruption. There are structures on some volcanoes, and they'll work if they're far enough away to not withstand significant impact from the eruption you're witnessing. (how's that for a non answer!?) But really, the most important thing to do is to get far away from an erupting volcano.

When the Teide on Tenerife blows, will it be the end of New York, or am I too Roland Emmerich here?

This is Mike. Tenerife and other volcanoes in the Pacific (Canaries, Azores, Cape Verve, etc.) have relatively frequent eruptions (El Hierro erupted in 2011-2012, and Fogo in 2014). But to get a big tsunami, you would need to cause a huge collapse. Those are pretty rare... Not as rare as far-fetched disaster movies, though...

Eruptions of Teide on Tenerife will affect people in nearby communities, but New York can relax. Recall that earlier computer modeling simulated collapses of the nearby island of La Palma. Modelers suggested that a collapse would send a tsunami to North America's east coast. That possibility has been well discounted by later researchers. But, before researchers could get their word out, a TV show about it became celebrity a dozen years ago, and it scared a lot of people.

I have a glass bottle (I think it was a 16 oz oj bottle; not home rn to ck) full of ash I gathered; I've never opened since filling it. I was living in a rural area along I-80 in California at the time and there was a surprising amount of ash. I can't imagine why anyone would, but is this something someone would want?

A lot of people ask this question. Back in 1980 people of the West collected thousands of bottles of Mount St. Helens volcanic ash as souvenirs. Now, homeowners are cleaning their attics and garages and wondering what to do with it. Scientists have all the clean ash that they need for analysis. So, the best use of your unwanted samples is donation to local expert science teachers or museums. A creative science teacher can figure out ways to use it in classroom instruction. Be sure that the bottle is labeled--where collected, by whom, and when. Thanks for asking!

What can we expect when Rainier erupts?

And another dumb question. What would happen if we were to drill into an active volcano? Could it release pressure causing an eruption? Could a vent be used to prevent eruptions?

This is Mike. Rainier mostly erupts lava flows, and eruptions aren't particularly explosive (especially relative to St. Helens and Glacier Peak). But there's a lot of snow and ice that can melt, even in a small eruption, and generate dangerous mudflows. As for drilling, this has happened! Magma was accidentally drilled by a geothermal operation in 2005 in Hawaii. Nothing happened. We can't really release pressure by drilling. That's often proposed as a "solution" to Yellowstone (which isn't really a problem anyway), but the scale of magma chambers is too vast to really pay attention to drilling, and magma has viscosity, so won't just release pressure when poked. It's not a dumb question at all.

Where would be the place on earth to study underwater volcanoes? Both with logistical obstacles and without obstacles?

Some great studies are happening right now about underwater volcanoes. Check out the studies on subduction zone volcanoes, like Havre Island (north of New Zealand) https://web.whoi.edu/mesh/research/.

Or mid-ocean ridge volcanoes: https://www.mbari.org/mid-ocean-ridge-explosive-eruptions

And hot spots too: https://volcanoes.usgs.gov/volcanoes/loihi/

So the choice of place to study underwater volcanoes depends upon the question you want to answer and the process you want to understand. But the good news is that there are several great studies already underway! -Heather

I saw a video of a volcano's dome collapse and subsequent pyroclastic flow the other day. it looked like rocks collapsing and then seemingly out of nowhere morphs from what looks to be a landslide into a full on cloud of superheated gas and ash. what's going on there exactly?

Good eye. The flows from a collapsing dome are scary, man. Is the one you saw of Unzen in 1991? Blocks fall off the dome , hit the talus slope below and just explode into dust, fragments, steam and gas. The whole mass races down the slope. My simple understanding - and I speak under correction from my learned colleagues with petrological expertise on this thread - is that the dome rock is hot, fragile and charged with hot gas under great pressure. When it falls and hits, it blows itself apart. The hot fragments surge downhill propelled by the explosion, aided by gravity and gliding on a cushion of trapped air, gas and steam. Note - heres an open invitation to my colleagues to comment. My understanding of this is just enough to keep me out of the way when it happens.

This is Heather. Andy did a great job with this answer. The transition from individual falling blocks to a pyroclastic flow relies on the presence of hot gases, ash, and large blocks. Dome collapse pyroclastic flows are called block and ash flows, largely because of this make-up. There are some great examples here: https://volcano.si.edu/learn_galleries.cfm?p=9

This is probably a question best suited for Seth. In what order do you rank the PNW volcanoes in order of greatest threat to lowest threat? Specifically interested in Glacier Peak and where it falls on the list.

Seth here. The USGS has ranked all 161 active volcanoes in the U.S. based on hazard and exposure -- the report can be found here: https://pubs.usgs.gov/sir/2018/5140/sir20185140.pdf . Across the U.S. there are 18 volcanoes considered to be very-high-threat. Of these, 8 are in the Pacific Northwest, including Mount Baker, Glacier Peak, Mount Rainier, & Mount St. Helens in Washington, and Mount Hood, Three Sisters, Newberry, and Crater Lake in Oregon.

Hello! I have a question. After 40 years, the forest around Mt. Saint Helens is recovering, however Mt. Saint Helen’s “bulge” is too. What is the probability that Mt. Saint Helens can erupt, possibly in the near future? If it is a high probability, what is the approximate amount of time until it erupts? Thank you!

Hi Anya_Arts!
Mt. St. Helens is one of the most well-monitored volcanoes in the US (very well-monitored). While volcanoes aren't actually "overdue," ever, monitoring allows scientists to detect signs when a volcano is preparing for an eruption, and to provide warning. The more monitoring, the better! Magma doesn't move through rock without giving some sign (shaking, releasing gases, causing uplift... these are the things monitoring detects)

So while we can't say exactly when it's next eruption will be, it will provide warning before it occurs. Unfortunately, exactly how much warning it will provide, whether it's days, weeks, or years - we won't have a good idea until it starts showing more signs of unrest.
-Brian

How accurate is the film Dantes Inferno, if you've seen it? In particular a scene where they are trying to cross a lake and the volcanic eruption has turned the lake into acid that is eating into the boat and kills the motor and they're trying to row across as quick as they can and the grandma steps out to make a desperate attempt to push them to shore, the acid eats her legs away and mortally wounds her

Would any of this be at all realistic?

Dear A_K, volcanic crater lakes can be pretty acidic--pH below 1, which is comparable to the acid in your high school chem lab. I doubt it would be strong enough to dissolve the boat or eat Grandma's legs away.

*Dante's Peak

Sincere thank you! You saved us from having to discuss the accuracy of the Divine Comedy!
-Brian

What's the latest on the "Super Volcano" under Yellowstone Park in Wyoming? A few years ago I was under the impression it would erupt at any moment, but I haven't heard much recently. Should I be worried?

This is Mike. There is so much misinformation online about Yellowstone. You have to be really careful about what you trust. It's a full time job fighting it, quite frankly. And there are lots of bad documentaries, too, many of which like to refer to Yellowstone as a ticking time bomb (which sort of seems redundant, but whatever) that is overdue. If you hear those phrases in a show, you know they don't know what they are talking about. Yellowstone has never been close to erupting, and it is not "overdue" (it doesn't work that way). There have been periods of elevated seismic activity -- like 2017, when ~2400 earthquakes were located as part of a 3-month-long swarm -- but much of this activity is related to faulting or fluid (water/gas) movement. The Yellowstone Volcano Observatory does monthly videos about Yellowstone activity (latest is at https://www.youtube.com/watch?v=4MeVcPuRO50&t=6s ), and we do a weekly web article about Yellowstone activity/history/research that is posted to the YVO website ( https://www.usgs.gov/volcanoes/yellowstone/caldera-chronicles). No sign of anything abnormal happening at Yellowstone.

How would you know if Yellowstone was about to erupt? I would imagine the early warning signs would be much much different from a cascade composite volcano...

Mike again. The signs would be huge. Most Yellowstone eruptions are lava flows, and not explosions. But regardless, we would expect an eruption to be preceded by many thousands of located events over weeks, and many of those would be strongly felt. Also, ground uplift on the order of meters. And overall geyser activity, thermal activity, and gas emissions would change park-wide (more than just changes at a single geyser, which is common). It would be unmistakable.

Hey guys! Much respect for your work!! I know this isn't in the U.S. but what do you think are the chances of Cumbre Vieja erupting?? That super volcano scares the hell out of me, with the possibility of the entire East Coast being flooded.. Do ya'll think this might happen in our lifetime?? Why or why not??

This is MIke. Cumbre Vieja is not actually a super volcano. It's actually more like the Hawaiian volcanoes. And the possibility of a tsunami hitting the east coast due to an eruption of that volcano is incorrect. It was modeled in a study several years back, but those models have largely been discredited (but not before the scary documentary came out!). There is no evidence for past such events. Ain't gonna happen.

Hi, I’m a new undergrad geology student right now and Volcanology has always seemed like one of the coolest parts of geology to get into. How did you become volcanologists? And do you know anything about the little volcano in Va called Mole Hill?

I enjoyed skiing on volcanoes and just followed opportunities that led me to hang out on them more often. In particular, undergraduate research was helpful to start networking and directing my graduate school path. Never heard about Mole Hill in VA, but aren't they all Mole Hills east of the Rockies? Sorry. Couldn't resist. --Wes

The 1980 Mount St. Helens eruption did a lot to spark my interest when I was 13. I studied geology in undergraduate school and came out to the UW for grad school to study volcano seismology. Since volcanoes are highly complex systems, observatories need people with lots of different specialties. At the Cascades Volcano Observatory we have geologists, geochemists, seismologists, hydrologists, geodesists, GIS specialists, computer programmers, field engineers, lab technicians, administrative specialists (to help us with the red tape that comes from working in a government agency), and outreach specialists. The thing connecting all those specialists is that we're all volcano nerds at heart and understand that we need information from all the other specialties to do our job. -- Seth

Where any of you living near Mt Helens at the times? Any interesting stories about how you modified your vehicle to get around?

People on the east side of the Cascades received one to a few inches of ash and had great need to be inventive. Envision pantyhose over air filters, for example. That was pretty common. But, ash also changed driving style. Truckers used CB radios to coordinate their slowing of traffic, thereby keeping ash on the roadway rather than whipped into the air. On May 25 1980, I got caught in ash from that day's eruption while driving north on I-5. We stopped every twenty miles to bang ash out the car's air filter. That 1970's era government-gray Plymouth Valiant got abused by gritty Mount St. Helens ash for multiple field seasons. The old beast became devoid of any paint polish and style, yet refused to die. Thereby, it was knighted "Prince Valiant." -Carolyn-

Plymouth Valiant's survive everything!

We had a white four door, coming home from a party (late 70s) my brother was driving. Misjudged stopping distance and hit the rear of a Porsche 911 stopped at light. 911 driver looked up and took off! (we had hit him). All we could figure out was he spotted the Valiant and thought it was the narc's and just took off. Ahem, it was a trick they used... tap your bumper, when you got out to investigate. Loved that car, never had a ticket never in. Four door Plymouth Valiant, long hair driver, everyone thought you were "Norby the Narc" (fed's n heads board game).

I passed though Portland OR two weeks later and dust was still thick and choking. It through every crevice in the car. We had been warned to take extra air filters. Seemed like every 30 miles, get out and shake out the air filter.

I remember seeing a Washington State Troopers vehicle. They had cut a hole in the hood and had a snorkel to a giant 18 wheel air filter to keep them running a full shift.

ParkieDude, thanks for your story! I don't know if ever we were similarly associated with being a Narc. Yes, we found MSH volcanic ash within the crevices of Prince Valiant for years after the eruptions. Yes, there was at least one police car with a snorkel, but not sure that it was a common solution. Live on, with great memories of your White Night Valiant!

I was 13 when it erupted and living in Massachusetts, so no stories from me. Carolyn Driedger was working at MSH in 1980 and has some stories that she will be sharing shortly.

USGS Volcanoes posted a few days ago that an active volcano is one that has erupted within a timespan of 10,000 years. Eruptions of volcanoes that had been quiet for 600 or so years such as Pinatubo in the PI and Chaiten in Chile have occurred quite recently. Statistically, what are the chances of an eruption from a volcano that has been quiet for 10 millennia? Thank you!

This is Alexa. This is exactly where time-averaged statistics get tricky and frankly not particularly useful. It's not uncommon for volcanoes go quiet for thousands of years, and then erupt several times in a cluster when they reawaken. This is where magma forensics studies come in - they help us constrain how the 'current state' of the magma system compares to longer timescales of eruptive activity for the volcano.

From my 7 year old- How do you know if a volcano is going to erupt?

There are a lot of monitoring stations on active volcanoes collecting data all the time. This establishes a baseline for what is normal at each volcano (each volcano is a little different). Scientists track data and when activity at a volcano moves beyond background levels, they take notice! They pay attention to (1) an increase in the frequency or intensity of earthquakes beneath the volcano, which could include volcanic tremor; (2) changes in the ground surface like swelling, subsidence, or cracking; (3) increased steam emission or small steam explosions; melting snow or ice; changes in existing fumaroles or hot springs, or the appearance of new ones; and increased discharge of magmatic gases. Once a volcano moves beyond background levels, scientists coordinate with emergency officials to make sure people who might be effected by an eruption know what to do. - Liz

Well, it depends of the volcano, but often there is an increase in earthquakes, the volcano may swell or there may be an increase in gases. But it could only be one of these things too! --Wes

What do you think of the Flat Brook Landing Formation Super Eruption(s) from 466 mya? It has the potential to be a "VEI 9" with ejecta of approx. 12 thousand kilometers cubed.

This is Mike. I had to look this one up. It appears to be a formation that erupted over a very long period of time (about 2 million years), so not a single event that one could classify with an explosive magnitude. There is a caldera associated with the volcanism of this time period, and the size (80 km in diameter) is pretty similar to Yellowstone. So probably not a VEI 9 eruption, since it would have been erupted in a long series of events which ultimately reached 12,000 km3 in volume.

I was a little surprised to see that the Long Valley Caldera is classified as a "very high threat" volcano, higher than any of the other volcanoes in the immediate vicinity, especially Mammoth. My understanding has been that the potential for a future eruption from Long Valley is exceptionally low and that Mammoth is far more likely to erupt (hence the volcano escape route from Mammoth Lakes). What about Long Valley makes it so dangerous as to earn its threat designation?

The threat level is based on the eruptive history, population exposure and infrastructure exposure (including airlines overhead). Mammoth Mountain hasn't erupted magma in about 50,000 years and Long Valley last erupted about 16,000 years ago. That being said, there is seismic activity beneath Mammoth Mountain and there is active discussions in the literature about the future eruptive potential of Long Valley Caldera. In the end, if you are a betting person, look north to the Mono-Inyo Cones for the next eruption. --Wes

What's the worst portrayal of a volcanic eruption/volcano behaviour you've seen in a movie?

This is Mike. "When Time Ran Out" is pretty bad. The cast is amazing -- Paul Newman, Bill Holden, Jacqueline Bisset, and so so so many more. And it was filmed on the Island of Hawaii, with some location shots at Kilauea. But it is so so so bad...

Do you know how an eruption of Mt. St. Helens would effect climate change?

I'll let an expert handle the technical side of this, but meanwhile, I can personally recommend that if you want a fantastic view into the crater of Mt. St. Helens, you should absolutely Climate!

-Brian

Well, thats a peak pun.

It's better than summits worse than others!
-Brian

Wendy here - When volcanoes are in a state of unrest, they release gases into the atmosphere. When volcanoes are not erupting but have magma stored within, this can be just passive outgassing. The most common climate-impacting varieties are carbon dioxide (CO2) and sulfur dioxide (SO2). During major explosive eruptions atmospheric interference can increase - not only are volcanic gases released, but small particles of ash also interact with the atmosphere.

CO2 from volcanoes is inconsequential in comparison to other types of activities (read here: https://volcanoes.usgs.gov/vsc/file_mngr/file-154/Gerlach-2011-EOS_AGU.pdf

Eruptions of lava, e.g. Kilauea are long duration and release a lot of SO2. The eruption in 2018 didn't have a large impact on global climate, but it definitely impacted downwind communities - not only Hawai'i Island, but also other islands in Hawaii. The 1783 Laki eruption in Iceland, caused a drop in global temperature. This resulted in crop failure in Europe and droughts in other northern hemisphere countries.

Mount St. Helens 1980 was the largest eruption in the conterminous U.S. in history, but it didn't impact the climate very much. It was much smaller than Pinatubo in 1991, which had a rather large impact. For Pinatubo, a significant amount (20 million tons) of SO2 was injected more than 20 miles in altitude and entered the stratosphere. This circled the globe and cooled the surface of the earth for 3 years following the eruption. The 1980 eruption of St. Helens possibly barely reached that 20 mi mark and it didn't include as much SO2 as Pinatubo. We would expect something similar in a future eruptive event...low SO2 for MSH. More found here: https://volcanoes.usgs.gov/vhp/gas_climate.html

What do you know about Greek mythology?....

This is Alexa. Volcanoes have been a source of fear and inspiration since the beginning of human history. Pele, Vulcan, Thor, Hephaestus. Actually volcano mythology is an entire cross-over field for historians, anthropologists, and volcanologists. Here's a brief primer http://volcano.oregonstate.edu/book/export/html/1015

Can anyone tell me why there are volcanos and volcanic flows in Arizona/New Mexico!? There aren’t any hotspots there (that I’m aware of) and it isn’t on a plate boundary. El Malpais NM confuses my amateur geology head🤯

This is Mike. That's a pretty complex area. The crust is thin due to extension, and there are some intersecting tectonic provinces, and that's the thought for a lot of the volcanism. For example, the margins of the Colorado seem to be a place where lots of magma can leak up. And the Rio Grande Rift sees a lot of volcanism. It's sort of a cracked, thin, and leaky area. To be technical about it...

Great question! Wendy here.

The western U.S. states host a lot of volcanoes! All these types of volcanoes are due to continental rifting. When there is spreading of the crust, mantle material can more easily rise up into the thin crust around the rift zone and erupt on the surface. In New Mexico, it's due to the Rio Grande Rift. Here's a Yellowstone Caldera Chronicles article I wrote on this very topic.

usgs.gov/center-news/yvo-not-just-yellowstone-meet-volcanoes-american-southwest

This is not a US volcano question, but I am sure you all would have an answer. 🙂 Mt Fuji, which majestically looms over Tokyo and environs is an active volcano. Last erupted in January 1707. Obviously millions of people now live in its shadow, much like Mt Rainer. How realistic would evacuating Tokyo be if Fuji were to reawaken?

Hi TheHistoryLass,
Good news! There aren't really any hazards that would cause a need to evacuate Tokyo - Typically the only need to evacuate is for people within immediate danger of Near-volcano hazards (lava flows, volcanic bombs, pyroclastic flows, etc.), or if they are within a lahar inundation zone. The only real way to ensure safety from these types of hazards is to not be there when they arrive. Fortunately, Tokyo is only really in the zone of ash hazards for these eruptions, when it is downwind, (as it was in the most recent eruption) - volcanic ash is disruptive, but not immediately life threatening. Check out www.ivhhn.gov for more details on ash hazard and how to protect yourself.

This is definitely good news, because we've run "pedestrian evacuation modeling" for lahar evacuation in even small cities around Mt. Rainier in the Lahar inundation zone, and this can be a challenge. One finding - it's critical that the people who are able to walk to safety don't get in their cars, because it would clog the roads. There are more roads in a city, but it would be extremely challenging to evacuate 8 million people in a timely manner if necessary.
Hope this helps! -Brian

Any particular favorite volcanoes amongst you lot? I’ve climbed and observed me a few. Tavurvur nearly got me once - second time I went up it, it ‘sploded the very next day, which would have been a bit of a downer.

My fave though has to be Mount Yasur - the most watchable volcano I know of. Got friends on Tanna, so regularish visitor. Interested in what your faves are and why - the asthetics, the activity level or some other feature.

I miss the lava lake at Kīlauea. There was something primal about watching the cooling surface slowly move apart as magma welled up from below, and see lava sloshing up on crater walls. We did a YouTube video from the rim in March 2018 with HVO's Matt Patrick (https://youtu.be/y0lNb4Hz7ac). Never realized the lake would start draining and lava would be erupting in the lower Puna in just a few months' time. - Liz

This is Alexa. My personal favorite is Mount St Helens. Where else in the world can you hike directly into the guts of a disemboweled volcano, still steaming, and look out across the plain of pumice and ash flows from source to sink? It's pretty dang special.

This is Heather. I love Crater Lake volcano - the beauty of the crater lake is surpassed only by the gorgeous geology of 400,000 years of volcanic eruptions displayed layer upon layer on the walls of the caldera! So cool!!!

This is Mike. I love Medicine Lake volcano, in NE CA. Not because it is super active, or you can see lava, or anything like that. But it's quiet and peaceful, and it has amazing geology, from basaltic flows to rhyolites, and some outstanding lava tubes in Lava Beds National Monument. And young flows (900 years). Even amazing culture and history. I did some of my first professional work there, so it has personal meaning.

This is Seth -- the volcanic landscape in Katmai National Park is amazing

Skiing Lassen and Shasta are my faves. --Wes

Has there been any activity lately? What kind of timescale are we looking at before it could be active again, if known?

The region is one of my favorites, being from Seattle, and I have a camping trip heading to the Mount Margaret Backcountry next month (if it opens), and hope to get another shot of St. Helens like this.

Hi f1del1us, If you're talking about Mt. St. Helens, it has an awful lot of seismic activity, which is just what it does. it's definitely the volcano in the cascades that has erupted most frequently in the last 4,000 years, and it will erupt again. This is the main reason St. Helens is the number 2 most high-risk volcano in the US (Kilauea erupts even more frequently, and people live on it's slopes).
However, because we know this, it's heavily monitored, and we will have some warning before the magma that is beneath it gets closer to the surface. However, whether that time scale is days, weeks or even months or years, we won't be able to tell until it begins showing signs of unrest. It takes an understanding of how quickly the lava is moving up the volcanic conduit in order to make forecasts about eruption activity timescales.

And good luck, I hope you can get backpacking soon!
-Brian

Nothing more than background in the Cascades. --Wes

I've been reading the Mt. St. Helens 40th anniversary daily on Facebook, and I don't see a lot of institutional admission of error yet. USGS expected a relatively small avalanche, not the huge lateral explosion it became. The majority of people who died were in areas open to the public that USGS thought would remain safe. But the early, and continuing popular story is that people died because they refused to evacuate. No, most casualties were not in places they were told to evacuate from. Will you be publicizing the error in prediction that caused the casualties?

Dear Cara, Larry here. You're absolutely right that a lateral blast was not expected--by volcanologists in the USGS or anywhere else. Prior to 1980, a lateral blast had never been witnessed or described by volcanologsts in the Western world. After the eruption, volcanologists found an analogous eruption from Kamchatka in 1956 (Bezymianny). But a lateral blast was--and still is--considered an outlier scenario among all the possibilities. It's an oversimplification however to say that areas open to the public were considered safe by the USGS . The USGS delineated areas that it considered hazardous, but the zones of public closure were designated by Dixie Lee Ray, Washington's governor, after considering the USGS zones, and lobbying by local groups. There is some discussion of this in USGS Professional Paper 1249 ( https://pubs.er.usgs.gov/publication/pp1249) .

After the eruption, the Washington Governor was on TV and essentially accused people killed in the eruption of violating restricted zones. This is untrue for nearly all, and the damaging statement have scarred surviving family members for decades. The Green River, for example, is many miles outside of any restricted zone. The people there, caught up in a sideways blast, skirted no roadblocks. They came to hike in the forest. They did nothing wrong. Prior to the eruption, the red and blue zones were drawn up by land managers with input by law enforcement, politicians, business people, and scientists. Since the eruption, the USGS has done a lot of work to develop volcano hazard maps that show areas affected by an eruption. Maps for the Cascade volcanoes are at https://volcanoes.usgs.gov/vsc/multimedia/cvo_hazards_maps_gallery.html. - Liz

I see you have listed quite a few "high threat" potentials.

• Crater Lake
• Glacier Peak
• Mount Baker
• Mount Hood
• Mount Rainier
• Mount St. Helens
• Newberry
• Three Sisters

As someone that lives basically in the shadow of Rainier and spends lots of time hiking/camping the cascade volcanoes, which of these "high threats" has the best chance of putting on a show anytime soon or is that a literal crap shoot?

This is Seth -- Over the last 4,000 years Mount St. Helens has had more eruptions than any other Cascade volcano, averaging something like 1 per century. Using the principle that the past is the best guide to what is likely to happen in the future, MSH is the most likely to erupt again. It's also one of the more restless volcanoes in the Cascades - it has the highest background seismicity rate in terms of numbers of earthquakes, and in 2014 the USGS Cascades Volcano Observatory released an Information Statement stating that there were evidence that a small amount of magma had been entering the system since 2008 and that this was a part of a recharge process that indicated MSH was still active with potential for an eruption years to decades down the road. You can find the Information Statement here: https://volcanoes.usgs.gov/volcanoes/st_helens/status.html

Based on the eruptive histories of the volcanoes, Mount St. Helens is most likely to erupt next. --Wes

Is Glacier Peak an “underrated” volcano? Seems like most Washingtonians know about Baker, Rainier, St. Helens, etc. Not a lot of love for Glacier Peak. Why do you think this is? Is it not active?

This is Alexa. Glacier Peak is pretty underrated. Few people realize it's the second most explosively active volcano in the Cascades behind Mount St Helens. But unlike Rainier, Baker, Hood, etc., the difference is that it's not easily visible from any of the main city centers (like Seattle or Portland). It looks like a lot of the other large peaks in the area.

How often do earthquake swarms happen in Yellowstone?

This is Mike. ALL THE TIME!!!!! About 50% of all earthquakes in Yellowstone are parts of swarms. Typically there are one or two a month, but they are usually small, with a few dozen events year. Sometimes they are Yooge! In 2017 there was a swarm of 2400 located events in 3 months. Most of these are due to faulting or fluid movement (water and/or gas). Note that the earthquakes happening near Salt Lake City and in central Idaho right now are not associated with Yellowstone. Those are tectonic quakes and aftershocks not associated with Yellowstone.

Serious question: Hypothetically, if science could allow for us to predict a massive volcanic eruption one year in advance would it do any good try and engineer a series of canyons to contain and direct the flow of lava to minimize damage to communities in the area or would that just be re-arranging deck chairs on the Titanic?

The idea of engineering ways to mitigate risk from natural hazards is long-standing. John McPhee has a great book detailing some past attempts: https://us.macmillan.com/books/9780374128906.

Several attempts to redirect lava have happened in the past. At Eldfell in Iceland (see the McPhee book), locals used fire hoses to redirect flows. At Etna in Italy, locals used explosives and built barriers to redirect lava with mixed success: https://pubs.er.usgs.gov/publication/70169254

But an important problem exists with engineering solutions and the sense of security that it bestows. Earthen dams thought to help redirect pyroclastic flows (which travel much faster than lava flows) overtopped and killed people at Merapi, Indonesia and Tungurahua, Ecuador. https://link.springer.com/chapter/10.1007/11157_2016_34. B

Pyroclastic flows can jump channels (especially at bends in a channel), so even the presence of a valley does not completely restrict the flow path to any particular direction.

Finally, as you say - a redirected hazard still travels somewhere...

-Heather

Book recommendations? :)

Study material or otherwise.

Here is the perfect binge-read for this weekend - "In the Path of Destruction: Eyewitness Chronicles of Mount St. Helens" written by USGS scientist Richard Waitt. It's all about the May 18, 1980 eruption of Mount St. Helens and has amazing survivor stories. - Liz

A really fun one that talks about the history of science, and the eccentric scientists who figured it out: "A Short History of Nearly Everything" by Bill Bryson

It has a couple great chapters about volcanoes and earthquake hazards!
EDIT - This was Brian

This is Mike. "Volcano Cowboys" is a fun one. I read it before starting work at the Cascades Volcano Observatory (about 20 years ago -- yikes!), since it chronicled the work of CVO scientists during the 1980 Mount St. Helens eruption, and also VDAP scientists during Pinatubo in 1991. Was a way for me to understand the contributions of some of the scientists I would be working with.

When does Baker or Rainier pop?  Are you monitoring Glacier Peak?

Glacier Peak is currently monitored with a single station, but more are on the way. A permit is pending with the Forest Service and we expect to be able to install four additional stations in summer 2021. Fingers crossed! --Wes

This is Seth -- Here is a link to a plot showing eruption histories of Cascade volcanoes over the last 4,000 years: https://volcanoes.usgs.gov/vsc/images/image_mngr/1000-1099/img1052_900w_722h.jpg . From that perspective, Rainier has had more eruptions over the last 4,000 years than Baker, so using the "the past is the best guide to the future" principle, Rainier would be more likely to erupt than Baker. Glacier Peak has a single seismic monitoring station ~5 km from the summit, the USGS is working with the USFS on a permit to allow installation of 4 additional stations around Glacier Peak.

What's your collected opinion on the Yellowstone supervolcano? What would signs look like if it were "getting ready"?

Overrated --Wes

Very funny Wes. Obviously the signs would look like this: Park Closed. - Liz

Jealous much, Wes? --Mike

This is Mike. If Yellowstone were "getting ready" to erupt (keeping in mind that most eruptions are lava flows, and not explosions), we would expect to see WAYYYY more activity than we do today. For example, many thousands of located earthquakes in a short period of time (weeks), with a number that are felt; ground deformation measured in meters over short periods of time. Massive changes in gas emissions and geyser activity across the park (not just at a single geyser); and so forth. Yellowstone's "background" activity is pretty high level, so if it were moving towards eruption we would see a lot more than we do normally.

What is the scientific consensus on Ice Cube's pyroclastic flow?

Hum..... Phat beat, bad definition! - Wendy

How does one become a volcano scientist?

Wendy here.

Determination!! It also takes a breadth of knowledge of many sciences, so lots of school. The great thing though, is that you can pick your favorite types of science then focus on understanding geology and volcanoes from there. Volcanologists can be computer scientists, chemists, physicists, GIS specialists, and communications specialists! Here's a great webpage with more info: https://volcanoes.usgs.gov/observatories/cvo/volcanologists.html

This is Alexa - USGS has a little summary here: https://volcanoes.usgs.gov/observatories/cvo/volcanologists.html. Let us know if you'd like to know anything more specific:-)

The Yellowstone hotspot- where did it originate and how much does the hotspot move versus the plate above it moving? Do hotspots ever die out?

This is Mike. The hotspot really got going about 16-17 million years ago, with the eruption of the Columbia River Basalts along the OR/ID and WA/ID borders. It eventually settled into a series of eruptions that progressed over time from the NV/OR border NE across Idaho to the present-day location of Yellowstone National Park as the North American plate moved to the SW. The hotspot does have some motion, but it is small compared to the rate of plate motion. So thinking about it as stationary is okay to a first order. Hotspots can die, but that's not something we've ever "observed", and the trails of many old ones have been erased by plate tectonics. They typically last for tens of millions of years, at least.

It seems that the lateral blast of MSH took everyone by surprise. Now that we know they are possible, are we able to recognise other volcanoes that might have had similar eruptions in the past (either in the Cascades or further afield?). And what might some other surprises be in future eruptions of the Cascade volcanoes?

Hmm. Larry here. It's pretty hard to anticipate surprises (that's why they're surprises!). We'd be pretty surprised to see another lateral blast. Caldera-forming eruptions happen more often than once or twice every hundred thousand years. And another flood basalt eruption would be even more surprising!

The lake that formed at the halemaumau crater collapse.... what acidity is it and what gasses are present there? How much do you anticipate this volcanic lake to grow?

Results thus far indicate an acidic lake, with a pH of 4.2 (neutral is pH 7). Interestingly, most volcanic crater lakes have a pH of less than 3.5 (more acidic) or higher than 5 (less acidic), which places the Halema‘uma‘u lake's pH squarely in the uncommon middle range. The current pH reflects the balance between incoming groundwater and the degree of SO2 degassing from below. The Halema‘uma‘u lake is still rising and will continue to rise until it reaches an equilibrium with groundwater. HVO webcams track the lake level if you want to take a look - https://volcanoes.usgs.gov/observatories/hvo/cams/KWcam/images/KWcam.gif . - Liz

How many Mt. St Helens would need to erupt to cover all of the land in the continental US with 1” of ash?

Hi RJP, it's Larry. Mount St. Helens erupted about a cubic kilometer of ash. The conterminous land area of the U.S. is about 8 million square kilometers. If you covered all that with an inch of ash, you'd need about 200 Mount St. Helens eruptions. Yellowstone's biggest eruption produced about 2,000 square kilometers of ash. Spread that over the entire U.S. and you'd have quite a mess!

Hello! I heard a rumor that a section of Oregon/Washington moves clockwise northeast slowly, but ongoing - then every 14 months some areas will stop and even move backwards. Is this true? If yes, what's the most recent research being done on it? Has something like this been observed elsewhere? What could it mean!

It is true. The 14-month process you mention is called "Episodic Tremor and Slip", and there has been a ton of research since it was first discovered back in 2001. The Pacific Northwest Seismic Network has a good website that summarizes what is known and also features a real-time map showing locations of tremor (non-volcanic) associated with this process: https://pnsn.org/tremor/overview -- Seth

What early warning signs do Cascade volcanologists look for when predicting an eruption or mudflow? Are they the same for say, Mt. St Helens and Mt. Rainier?

This is Seth -- One thing we've learned from volcanoes around the world is that every volcano does things slightly differently when it wakes up. Some have lots of earthquakes, some have lots of deformation, some have lots of gas, some have all three. The important thing is to have a monitoring network in place with seismometers, GPS receivers, infrasound sensors, webcams, and gas-monitoring equipment that is capable of detecting whatever signs and symptoms are generated by a volcano.

How common is it for a composite volcano like Mt. St Helens to erupt in a lateral blast? I listened to a speaker who believed that there was evidence of lateral eruptions triggered by massive landslides in the ancient Absarokas.

Lateral blasts have been observed at many volcanoes. The tell tale sign is a remnant deposit of hummocks (small hills) that radiate out from the volcanic edifice. For example, there was one from Mount Shasta in California over 300,000 years ago (https://www.usgs.gov/volcanoes/mount-shasta/hummocks-indicate-large-eruption-shasta). Also, Bezymianny volcano in Kamchatka Russia (https://volcano.si.edu/volcano.cfm?vn=300250) erupted with a lateral blast in 1956.

Did any of you get to see the Leilani breakout in Hawaii? That lava through the channel towards to ocean was moving really fast for many days.

What's the fastest lava flow ever recorded and how are flow speeds calculated? Thank you!

Several of us were in a rotation in Hawaii for the 2018 eruption. For that eruption, speeds were measured with a radar gun (and by drone w/ pixel tracking on video). I measured 25 mph myself and can imagine that it got upward of 30 mph. --Wes

Heather, you mentioned in a previous comment about volcanic event tree forecasts. What exactly is that? What are the steps involved? Any resources you can give about it?

Thanks so much for being here!

An event tree is a logic tree that lays out possible scenarios for evolution of volcanic unrest. There is an example volcanic event tree schematic at: https://volcanoes.usgs.gov/vhp/forecast.html.

At each branching junction in the tree, there are a variety of possible outcomes. This framework for eruption forecasting can be used to discuss and/or detail relative likelihood of the occurrence of different events, the products that they might produce and even the distances that they may travel. The actual likelihoods of different branches (scenarios) are informed by monitoring data, eruptive history, the morphology of the volcano, models of eruptive activity, comparison with other volcanoes and other eruptions. -Heather

What is the most unexpected mineral found in the eruption of Mt. St. Helens? And what can that mineral tell us about its magma chamber dynamics?

leaverite

Although not present in the products of the May 18, 1980 eruption, the most unexpected mineral found in any Mount St. Helens volcanic rocks is cummingtonite, a commonly metamorphic mineral: https://en.wikipedia.org/wiki/Cummingtonite

Several eruptions that occurred more than 3,300 years ago contained this mineral. Table 4 in this report shows mineralogy of many explosive eruptive deposits of Mount St. Helens: https://pubs.er.usgs.gov/publication/sir20175022D

-Heather

This one is for Heather but can be answered by anyone:

What did we do correctly to prepare for the Mount St. Helen's eruption in 1980 and what do you think we could have done differently to prepare? Along with this, how could we prepare for future eruptions of other Cascade Range volcanoes?

In 1980, scientists ramped up monitoring efforts quickly, redirected staff to focus on the new crisis, integrated diverse information together in order to forecast eruptions - all of these efforts were a great success. But we learned so much from the May 18th eruption, especially about the hazards associated with a 'lateral blast': the speed, the direction of blast, the extent of possible damage. After the May 18th eruption in 1980, scientists pioneered several new techniques: with incredible success forecasting explosive eruptions in 1981! And with new techniques of forecasting and communicating risk to stakeholders that have been used around the world since that time (volcanic event tree forecasts). How can we prepare for future eruptions? 1. Learn more about the eruptive histories of these volcanoes 2. Help communicate the potential hazards from volcanoes, by educating ourselves and others 3. Continue to develop our understanding of the volcanic systems and methods for forecasting eruptions. -Heather

Is there any study that goes into the effects of global warming on volcanic activity? Would a couple degree change in the climate increase the likelihood of eruptions?

There isn't really a relationship on volcanoes from climate changes. However, there is some impact of volcanoes on climate. Sulfur dioxide emissions, in particular, can cause temperatures to fall around the globe. This occurred after the Pinatubo eruption in 1991. Here's a website with more info: https://volcanoes.usgs.gov/vhp/gas_climate.html - Wendy

Late to the party. How closely do you look into other volcanoes? Do you have a favorite volcanoe outside of the ones you monitor (like Mount Etna, Fuji, etc.) and why?

We definitely pay attention to what our colleagues are learning from eruptions at volcanoes around the world, and there is a group based at the Cascades Volcano Observatory called the Volcano Disaster Assistance Program that works with other observatories as requested. For me, there are many volcanoes that I find fascinating, but the eruption that first peaked my interest in volcanology was the 1973 eruption of Eldfell in Iceland (https://en.wikipedia.org/wiki/Eldfell). -- Seth

We have a long lasting bi-National Exchange with Colombia, where we work with people who responded to the 1985 lahar at Nevado Del Ruiz Volcano, and help make sure that type of tragic eruption doesn't happen in other places in the world, or there again. We can learn a lot from other eruptions, and also share best practices - Volcano Preparedness is an international effort!

I love the Kamchatka volcanoes around Bezymianny and Kluchevskoy. --Wes

What effect does volcanic activity have on global warming, especially compared to forest fires and human activity as two other bug sources of greenhouse gasses?

We actually addressed this in a website article. Basically, volcanoes have nothing on human activity when it comes to climate change. - Wendy https://volcanoes.usgs.gov/vhp/gas_climate.html

What’s your favorite volcano and why?

All of them except Yellowstone --Wes

Wes is just jealous. --Mike

You're just mad because it hasn't erupted in 70,000 years. - wendy

What is the likelihood of the Long Valley Caldera (North of Bishop) eruption in the near future, or Shasta and Lassen for that matter?

This is Mike. Long Valley itself is not the most likely volcano in eastern California to erupt. North of Long Valley is the Mono-Inyo chain of craters and lava domes. The last eruption in that chain was only a few hundred years ago. Most Long Valley eruptions are lava flows. The odds of a big explosion there are pretty small. Lassen doesn't see many eruptions -- only 3 or so in the last ~10,000 yeas (all of which happened in the past 1100 years!). Shasta has been far more active in the past 10,000 years.

Undergrad majoring in geology here. Do you have any recommendations for field camps?

Many field camps have been disrupted this year because of COVID19, but there are many online field camps this year listed at: https://nagt.org/nagt/teaching_resources/field/summer_2020_virtual_field_camp.html

-Heather

Do you have bets on when different volcanoes are due, and if so: which would be the top three?

This is Mike. In the lower 48 states, the #1 answer will always be Mount St. Helens. It's by far the most active in the Cascades.

Were you able to detect a clear uptick in activity at St Helens before the eruption? Was there anything that would’ve led the team to believe an eruption was inevitable? 🌋

Not the scientists from the AMA. However yes they were able to detect things, many weeks, even months before! They detected earthquakes, increase in gasses, and closer towards the eruption a giant bulge on the side of the mountain was growing about 5-6 feet per day. The USGS Twitter has been doing “flashbacks” to the eruption 40 years ago. Scroll through their timeline and they talk about major events that occurred before the eruption! USGS Twitter

This is Mike. Great answer, thanks!

This is Mike. Flipslips is spot on. There were 2 months of precursors before May 18, 1980 -- bulging of the volcano, lots of earthquakes, and small explosions. And there was a week to precursory activity before the 2004 eruption. Most volcanologists did think an eruption was inevitable in 1980, but the lateral blast was mostly an unknown phenomenon at the time. The impact was larger than expected.

Hope you guys are okay! Stay safe. I’m really interested in Krakatoa, so my question is if it was to erupt today what would the results be? Thanks!

This is Mike. Actually, Krakatau has erupted, very recently. There was a significant collapse (generating a tsunami that killed several hundred people) in late 2018, and just recently there was an impressive explosion (albeit a small one). The island is mostly gone, so any large eruption now would be quite different than 1883, and might involve a lot more seawater (although that clearly also played a big role in 1883).

Are there any plans to deal with a Yellowstone eruption? Do we emergency response plans for seismic / volcanic events?

This is Mike. There's really no way to "deal with" a Yellowstone explosion (most eruptions are lava flows, mind you, and there's not much to be done with those, either). The Yellowstone Volcano Observatory does have a response plan for the event of unrest (https://pubs.usgs.gov/circ/1351/). But the plan for how evacuations, etc. would be managed is the responsibility of local emergency managers. Yellowstone National Park does have a plan for dealing with various types of crises -- like earthquakes, weather events, etc. They think about that sort of thing a lot, since there are so many people that visit during the summers.

Which volcanoes should we be worried about?

The USGS has ranked all 161 active volcanoes in the U.S. based on hazard and exposure -- the report can be found here: https://pubs.usgs.gov/sir/2018/5140/sir20185140.pdf . For the Pacific Northwest, the 8 highest-threat volcanoes are Mount Baker, Glacier Peak, Mount Rainier, & Mount St. Helens in Washington, and Mount Hood, Three Sisters, Newberry, and Crater Lake in Oregon.

What's the temperature difference between lava and fire, and how close can you get to it without burning? I know the temperature must have a range, but in general.

Hi FP. Well, I know magma temperatures pretty well but had to look up the one for fire. Magma temperatures are around 800 to 1200 degrees Celsius--rougly 1700 to 2,000 Fahrenheit. Basalts, like the stuff that flows out in Hawaii, are on the hot side and rhyolites, like Yellowstone, are on the cool side. Typical wood flame temperatures are about 600 C (1200 F), but it depends on what you're burning. Throw a piece of rhyolite into your campfire and it won't melt.

So I'm headed to Big Island this summer for university. I get notifications of natural disasters via text from their DOH and I get a lot of earthquake notifications averaging about a 3 on richter scale, mainly in near south point. Can these earthquakes set off any of the volcanoes there?

Earthquakes in Hawaii can trigger eruptions, and vice versa. But the earthquakes must be very large and the volcano must be already very close to an eruption. The most recent example is the 1975 Kalapana Earthquake (M6.9) which triggered a small eruption at the summit of Kilauea. At Mauna Loa, large earthquakes often precede eruptions. Magnitude 3 earthquakes don't have enough energy to trigger eruptions in Hawaii, even if the volcano is very close to erupting. --Wes

So Craters of the Moon NM is a remenant of Yellowstone hotspot being under the earth and having a little “burp” of lava ya? It only erupted 2000 years ago. Do we expect anymore of these burps from Yellowstone along the snake river valley?

Wendy here. Craters of the Moon volcanism is not related to Yellowstone. It's actually due to thinning of the continental crust in the intermountain west as a result of Basin and Range extension. And yes... Craters of the Moon will likely have another eruption! Here's a Yellowstone Caldera Chronicles article about that very subject:

https://www.usgs.gov/center-news/craters-moon-idahos-last-and-next-volcanic-eruption?qt-news_science_products=1#qt-news_science_products

Is there any truth to solar minimum affecting an increase in volcanic activity? I have often read that cosmic rays during times of low solar activity actually causes and increase in volcanic activity.

Nothing that would be useful for forecasting. --Wes