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After many months of seismic unrest, Alaska's largest city prepares for a possible volcanic eruption from Mount Spurr.

If we see energetic volcanic tremor begin beneath the volcano, then that will be a signal that the volcano is progressing even closer to an eruption.

What are the risks to Anchorage and other central residents, and how should you prepare?

We'll discuss it right now on Alaska Insight.

Mount Spurr last erupted in 1992.

The volcano, located about 80 miles west of Anchorage, has had elevated seismic activity.

Ground swelling and gas emissions for many months, and scientists say an eruption is likely.

The aviation alert for it is at yellow right now.

And the big question on many minds is when an eruption might happen, and if the wind will blow ash toward Anchorage or away from the state's main population center.

Tonight we'll hear from scientists and emergency managers about the risk and how to prepare to stay safe.

Before we get to that discussion, here are some of the top stories of the week from Alaska Public Media's collaborative statewide news network.

The Alaska Department of Fish and Game is imposing what it calls unprecedented conservation measures to address declines of Gulf of Alaska Chinook salmon, also known as king salmon.

The species is currently under review for listing under the federal Endangered Species Act, the department said in a March 18th announcement.

It will be restricting western Alaska king salmon fisheries, including in Kodiak and Sandpoint.

The measures reflect a broader shift in strategy, according to the department's.

It's unusual to restrict multiple fisheries based on concerns for Chinook salmon across the Gulf of Alaska.

It reflects an effort to distribute conservation burdens more evenly across the regions that encounter Gulf of Alaska Chinook.

The restrictions apply only to person and are limited to July.

Four new faces are set to join the Anchorage Assembly, according to initial election results from Tuesday night.

With more than 39,000 ballots counted, Yarrow, silvers, Erin Baldwin, De and Keith McCormick are the leading candidates to represent East Midtown and South Anchorage, respectively, while Jared Joker is poised to represent Eagle River Chugiak.

The two incumbents, North Anchorage's Daniel Volland and West Anchorage's Cameron Perez Padilla, are leading in their bids for reelection.

The six elected Assembly members will each serve three year terms on the 12 member body.

Election officials will post additional results over the next two weeks, with results set to be certified on April 22nd.

Alaska has returned to a period of slow but steady population growth as births outpaced deaths, marking making up for migration out of the state.

A state Department of Labor and Workforce Development report found that the statewide population has been trending higher since 2020, and the increase appears to have accelerated in 2024.

The state's population surpassed 740,000 people for the first time this decade in 2020.

For that's nearly 8000 more people than lived in Alaska in 2020.

State demographer David Howell attributed the bulk of that growth to the rail belt running from Kenai up to Fairbanks.

The Mat-su borough has had consistent growth for decades.

That is in sharp contrast to other regions.

The population of every borough in Southeast Alaska has declined since 2020.

Western Alaska has also seen its population decline over the same period, but for a different reason.

The population there is very young, with many people moving to hub communities or out of state.

You can find the full version of these and many more stories on our website.

Alaska public.org or download the Alaska Public Media app on your phone.

Now onto our discussion for this evening.

For decades, scientists have monitored Mount Spurr.

The volcano, about 80 miles west of Anchorage, has erupted twice in the past once in 1953 and again in 1992, which left a quarter inch of ash on south central communities.

Alaska Public Media's Matt Fabian went to the Alaska Volcano Observatory and spoke with researchers about monitoring the current unrest at Mount Spurr.

All right, let's step into the Aveo operations room.

This is where we conduct our hour monitoring of our real time data coming in from our remote stations.

This is showing a a webcam located here in Anchorage.

And it's pointed at Mount Spurr.

If you come over here, you can see another part of the operations room where where not just looking at the number of earthquakes being located, but we're looking at the seismic data itself.

One of them that we're looking for very closely at AVO is called volcanic tremor.

Volcanic tremor is a long time continuous shaking of the volcano for minutes, tens of minutes, an hour, or even longer.

If we see energetic volcanic tremor begin beneath the volcano, then that will be a signal that the volcano is progressing even closer to an eruption.

Yes, this is the tephra lab, and we want to be able to get as much information from that ash as we can about the volcano.

This is a sample that actually fell in Anchorage in August of 1992.

And if you look really closely, it's a very coarse grained ash.

It's very gritty.

In some ways this is not as bad for your health as a lot of volcanic eruptions, because the grain size is coarser, so it doesn't get into your lungs and it's not not quite as hazardous.

However, we've also been looking in our archives and from samples that people had given us over the years from the 1953 eruption.

And it's really fine grained and really powdery, and this stuff would get resuspended more easily.

It would get into your equipment more, into your house more, and also potentially be more dangerous for your lungs.

So we're looking at all of these old samples to understand the range of what Spurr can produce to help people prepare.

And that's the aim of tonight's discussion, clarity, to help us better understand how to prepare for the potential of ash falling on Anchorage after a mount SBR eruption.

With me this evening is David Schneider.

David is, geophysical geophysicist or volcanologist, I guess either works, Yep.

With the Alaska Volcano Observatory.

And Kerry Whittaker is the disaster recovery coordinator for the city of Anchorage.

Welcome, both of you.

Thanks so much for being here.

David.

Be here.

So, David, I am fascinated by that discussion of volcanic tremors.

I had never heard of that before.

What?

What's known about this activity?

And is it what happens?

Is it a violent shaking that dislodges outside debris?

Is it from magma coming up into chambers?

What is.

And it's a great question.

And, you know, it's funny.

There really is no like one true source of tremor.

There's lots of processes that can lead to it.

But you can think of it mainly as like a fluid moving through a pipe.

And so just like, you know, a pipe organ has, has, fluid air moving through it and it causes a resonance and it gives off a tone.

Same thing with volcanoes.

So fluids moving in a volcano, either from gas or other sorts of other sorts of fluids, like water.

You know, that would cause a constant shaking of the ground and lead to this process.

It's not anything that anyone would feel.

Even if you're on a volcano that's experiencing it, it it you would never even feel.

It's just much too subtle.

Okay.

So the size seismic, sensors that you have there would pick it up, but, yeah, they're extremely sensitive.

And, you know, some volcanoes, such as Sheldon, which erupted, a couple of years ago in the Aleutians that was really characterized by this long period of tremor that was related to the magma moving up, prior to an eruption, spurs a little bit of a different beast.

And how in how we categorize volcanoes.

But again, it's just that sort of movement of, of fluids like gases or liquids or in some case, magma.

So just being able to differentiate that is something that the seismologists would be doing really interesting.

Is there any sort of I know that that would give you an indication that perhaps an eruption is imminent.

Does that activity go on?

I guess he said it could last for minutes or even days, Yeah.

In 1992, the first eruption was preceded by tremor.

That was, you know, in the weeks before the final eruption.

And that's what we've been telling the public, that even though we're at aviation color code yellow and ground alert advisory to get to that next level, that would really be like a continuous we would term would have to be more continuous, and it would likely be in the in the weeks to days prior to an eruption.

Okay.

Earlier this week, your colleague was on Alaska, talk of Alaska with us, Christy Wallace.

And she noted that seismic activity in ground deformation had subsided a bit in the, in the past week.

What do you see today for activity amounts for, you know, all volcanoes, you know, that are in a period of unrest, the activity will wax and wane like some some weeks you get a little bit more, some weeks a little bit less.

So right now what we've been telling people is we're really not accelerating or decelerating in any, any great to any great degree.

And that can have a really long fuze prior to an eruption that can really last months.

And so we're not trying to be too wishy washy about that, but that's just how volcanoes are.

You can think of like if you light a fuze and sometimes, you know, at the end when the fuze gets to the dynamite, you know, it goes bang.

Sometimes it goes, it's a dud.

And so at this point there's really unless things are increasing or decreasing, we're just in that sort of we think the fuze is lit, but we don't know exactly when it'll when it'll go off and whether or not or if it'll go off the chart.

Yeah.

Of course.

Yeah.

Carrie, thanks for your patience here.

You also joined us on Talk of Alaska earlier this week.

Describe the plan the city has in place for both notifying people if an eruption occurs and other measures that both the city is undertaking and you want citizens here to do, to be prepared to shelter in place for a period of time?

Well, we always recommend it's standard practice in Alaska to recommend people have, at least a two week emergency preparedness kit on hand.

And we have earthquakes that we have no notice about.

It's nice to have some notice for once, for the volcano.

We can go through our emergency kits and make sure we have all of our supplies.

People with, particular vulnerabilities, preexisting lung conditions in particular, may want to be extra certain they have N95 masks on hand, that they shelter in place longer to avoid the ash.

But it's really all we advise people to have is the standard emergency preparedness kit, which is roughly a two week supply of food and water on hand, because if we had a major earthquake, we wouldn't have this kind of notice to be ready.

This is a great opportunity for people to go through their kit and make sure they don't have a bunch of expired granola bars in their, and in terms of, the cleanup and alerting, there's a lot of ifs in our plans because we don't know if or when the volcano is going to go off.

We don't know what direction the wind is going to be blowing when it goes off.

So, we are encouraging everyone to sign up for, the rave alerts, which we have that information on our website and on our Facebook page.

You just text the, the word Anchorage to the number that we have listed, and you get signed up to get the rave alerts.

If you already get the, the, alerts that Anchorage Police Department sends out, then you're already signed up.

If we sense that it's an imminent threat, we absolutely have the capability to send out, and, emergency alert system message like the ones that go across your television screen.

And we're working out the, the instances when we're going to potentially do that and the language we would use and whether or not that goes out over what system.

But if you sign up for rave alerts, if there's an emergency, you'll know it.

And I know that you've got a, assess what kind of alerts you'll be sending out based on what actually happens.

But do you anticipate that you will send out an alert?

Initially, if an eruption does happen, regardless of what we know yet about wind direction or anything, will you be sending out an alert?

Oh, monster's gone off.

It's highly likely that we'll send out at least a rave alert.

That's that, I can say for sure.

Everything else is sure.

Kind of up in the air.

Depends on what's happening.

And, and and they're working out the plans and, and the instances and talking about because do you want to be woken up in the middle of the night if.

Well, I'm in the news business.

So yes, if it's not coming this direction or, you know, that's.

Yes, I always want to be I want to be right in the front line when so that everybody does know.

I know, of course David, we in the video that we saw, we saw the difference in ash from the 1992 eruption.

Larger, coarse, coarser ash in the 1953 eruption, finer particulate, bad for lungs if both eruptions came from the same crater peak, what does the difference in ash indicate?

Is it the force of the eruption or what?

What changes it?

Yeah, that's an excellent question.

And, you know, our geologists have been going back and looking at that, you know, one mechanism to produce finer ashes, to have more water involved in the eruption.

So in 1953, there was actually glacial ice and snow in Crater Peak.

And so one hypothesis is that, because of all that availability of water, you get the fragmentation is much greater.

And that's pretty standard for volcanoes.

So more water in the eruption can produce finer grained ash.

In 1992 there was a lake in Crater Peak, but it absolutely changed color and then dried up and blew away prior to the eruption.

It was kind of a thing.

So that was indication that a lot more heat had was available.

And so there wasn't really that source of sort of vent water.

So I think that's kind of our leading hypothesis right now as to why that is.

In addition, you know, like stronger winds will will move ash, coarser grained ash, you know, more, coarse, coarser grained ash, the fallout versus like calmer winds because the coarse grained stuff is followed up near the volcano by the time it gets over to Anchorage, maybe only the fines are left.

That's probably not the case here.

Because even if you look at the ash near the volcano, my colleague Christy has done that in the past, along with the other geologists.

It's very fine grained, very near the source.

So it's probably an influence of water.

Although that deposit wasn't well studied in 1953 because Alaska wasn't even a state at that point.

And there really wasn't that level of of sampling.

That that went on back then.

The Alaska Volcano Observatory has an ash cloud forecast web page, which is kind of cool to look at that modeling.

Tell us about how this would be used when and if spur erupts.

Yeah.

That's so that that that work really is the fruit of of of the labor that started after the, the 2009 eruption of Rita when there was a little bit of ash fall in Anchorage, and we realized there really wasn't a model that was going to predict based on the eruptive conditions and the weather in the winds, like what was going to happen.

And so, a group of, of USGS, you know, modelers and geologists got together and developed a model called ash 3D.

And so this model is run, twice each day for just a sort of a logical size eruption of Mount Spurr.

And that's put on our web page, and it forecasts the thickness and as well as the timing of when ash fall to occur.

If we're to rupture these at these specific times during an actual eruption, we will be updating that with the start time and cloud altitude, and that will get updated on our webpage.

Then the National Weather Service, the Anchorage Forecast Office, who has a responsibility for issuing ashfall warnings, takes that information and incorporates it into the their their warnings.

In addition, we're running a series of models each day that look at a variation in eruption, cloud height and and timing and that produces like how likely it is that, ash would fall in in particular areas.

And that's run for like the current day, the next day, in the following day.

And that just gives you like the big picture, you know, one and two days out.

If the volcano were to erupt, what areas would be impacted because not every area is going to be impacted the same during an eruption.

That's a big message that we're trying to get out.

And so that's also available just for more planning purposes.

And I think it's much more useful to the public and to various sectors.

If the volcano were at elevated alert levels than where we are right now.

At this point, it's nice to look at you can become familiar with it.

It'll become much more useful, I think, if we're moving closer to an eruption.

All right.

Thank you.

Carrie, when we were on talk of Alaska discussing this, you mentioned that ash is more likely to be a nuisance rather than a true hazard.

And so the big takeaway is just be ready to hunker down for some period of time.

Especially if the air looks foggy or cloudy.

And that would be an indication that there's particulates suspended.

And folks should stay out of that.

What makes sense, though, for preparation, I see people buying goggles and masks for their dogs and, you know, kind of going over the top with some of these preparations.

I adore my dog, but, I have no plans to buy her any dog goggles.

So what what are you recommending to folks?

And that's absolutely a personal choice, right?

I mean, I completely, completely understand people wanting to take care of their pets and pets.

Spend a lot of time outside.

The we've been working very closely with the state of Alaska to, have, a really comprehensive, frequently asked questions on their website ready.alaska.gov.

That is the best place to go with any questions or concerns that you have.

We it's updated regularly every time someone comes up with a question we haven't thought of yet, it gets added and updated.

And it's, it's a working group of everybody involved in public information.

We run everything by the experts at the Aveo.

That's the best place to get information about animals, people.

The main thing is if you for people with, preexisting conditions that are particularly vulnerable to stay inside during ashfall and to have, especially and 95 masks on hand if your lungs are particularly sensitive, goggles are a great idea, especially if you're going to be outside cleaning up, working in it.

It's it's all very commonsensical.

Like, it's not we don't need to take anything extreme.

And one of the main things that people should remember too is it is very, very abrasive.

So yes, you don't want it in your lungs, but also you can't wipe it off of things.

You're going to have to use water to spray it off or you'll be scraping, scratching things.

But it's also not going to take a ton of water.

You're not going to need to do it.

It just takes a minimal amount of water to to clean up.

Yeah.

So I think the other thing that's important to realize is that there's, you know, the size of the particles really matter in terms of like the health hazard and air quality folks from both the state and the Muni.

We have air quality monitors here that measure particular sizes, and they will be issuing air quality advisories if the particle size is especially fine grained, even for people without respiratory conditions with smaller than about ten microns, which is really, really, really small, you can breathe that in, it gets into your lungs.

And even if you don't have respiratory issues, you don't want that to happen.

Yeah.

So so that is something that those agencies are we've been working with them all the everyone's been working with them and they're ready to go to measure those particle sizes.

Interestingly, in 1992, even though it fell is a very coarse grained ash, people driving on it and sort of routine activities broke it up into smaller particles.

And the air quality actually was worse in terms of fine particles in the days and weeks after the eruption than it was during the ash fall.

And so that's a really important thing.

People remember, too.

It's not just a one time that I believe is one of the drivers between this effort to clean it up as quickly as we can afterwards, to kind of minimize that risk, it makes sense.

David, a gentleman called, this week convinced that because there's been a lot of volcanic activity on the Aleutian arc and because Mount Spurs close to the now to the Denali fault, he is very anxious that a huge Mount Spurr events could trigger a catastrophic eruption and massive Denali fault earthquake.

Is there any concern or any connection that the Aveo scientists have seen in this regard, or any historical evidence that one event could trigger a nearby fault earthquake to occur?

You know and you know what to make, you know, it's easy to to just say, well, you know, make make fun of people that might think of that, not really make fun.

But just like I understand the concern that people have, I think that's the best way to put it.

People are always concerned about this relationship between earthquakes that they can feel and eruptions, because they're really separate processes.

They're they're related in that we're on a plate boundary.

But the kinds of earthquakes that you feel here locally, you know, that are due to tectonic forces are really, really different than the ground breaking earthquakes that happen at a volcano when new magma comes in.

And so even like a earthquake on a, on a fault is not going to trigger an eruption.

An eruption is not going to trigger those kinds of potentially destructive earthquakes, in other areas.

Okay.

So it's not a Hollywood movie we don't have to worry about.

No, but and lots of people have that concern.

And so I don't want to like, downplay people's concern.

And it's like, I think one of those sort of common things, especially in social media, people talking about a lot.

And it really points out to the need to search for other authoritative sources.

Most YouTube videos aren't that and so but some are very some are right, some are really good, but some aren't.

And I'm not.

You know, I'm not trying to like, you know, pick on that.

But it's like try to seek out authoritative voices if you have got questions and you can always write to, you know, ask a volcano observatory and ask that question.

And it's a frequently asked question.

And we can we can help people alleviate their fears.

That's that's what this is about.

Yeah.

Fantastic.

Kerry, there was some guidance that went out saying that if an eruption happens and ash comes over the city, people should stay inside for four hours or so.

Is that just sort of a general guidance or where did that number come from?

That number came from our our friends at the AVO.

It's what the ash fall events have lasted in kind of that general timeframe in the past.

And that's the information we have to go on.

So that's our expectation is roughly four hours.

The main, recommendation is to stay inside shelter in place during ash fall.

So as long as the ash is actually falling in your area, stay inside, stay out of it.

And, but once it's settled, once it's no longer falling, you can go about your daily business, maybe try to not drive around as much, if you can, to, so that we can clean up.

But don't cancel doctor's appointments, go to the grocery store, do the things that you absolutely need to do.

But when the ash is actually falling, shelter in place.

Yeah.

And ahead.

So, you know, in 1953 and 92, there was a period of time when like it was dark in certain parts of Anchorage, like, you know, the streetlights came on and so, you know, but that's not everywhere.

That's down the axis of where the plume would be.

And at the edge it gets it's less extreme.

And so it really is sort of like specific.

It's like real estate.

It's location, location, location, you know, and wind direction.

Yeah.

And wind direction.

So so you know, I think some of the guidance is it's like general guidance.

But you still kind of have to apply a little bit of like observation to what's going on in your area I think is important for people to.

Well, thank you both so much for being here and thank you for the work you're doing and helping us all prepare and be ready.

Yeah, we're happy to be here.

Thanks.

Don't panic.

Make a plan.

No one can say with certainty when or even if Mount Spurr will erupt, or how disruptive an eruption would be.

But the main thing to remember is not to wait to make a safety plan with your family.

Do it now when you can calmly prepare.

Stock up on filters for your vehicles and home heating system.

Swim goggles to protect your eyes from abrasive ash.

Extra drinking water, food and medicine so you'll be ready to shelter at home if an eruption occurs and ash drifts over Anchorage.

That's it for this edition of Alaska Insight, visit our website.

Alaska public.org for breaking news and reports from our partner stations across the state.

While you're there, sign up for our free daily digest so you won't miss any of Alaska's top stories of the day.

Thanks for joining us this evening.

I'm Lori Townsend.

Good night.