This message comes from U.S.
Bank.
Simplify how you do business with Business.
Essentials a powerful combination of no monthly maintenance fee checking and card payment processing.
Deposit products are offered by U.S.
Bank National Association.
Member FDIC.
You're listening to Shortwave from NPR.
Hey, Shortwavers.
Emily Kwong here and Hannah Chin with this month's installment of Nature Quest.
And...
Emily, full disclosure, I'm doing something a little bit selfish today.
Instead of answering a real listener question, I'm using my producer privilege TM to investigate a question that I've had for a while about earthquakes.
Okay, tell me more.
So I'm from Portland, Oregon, and Portland is not a hot spot for earthquakes.
We just don't experience them multiple times a year, you know, the way Californians do.
Yeah.
But Portland is right next to the Cascadia subduction zone, which is this underwater fault line in the Pacific Ocean that stretches from Canada all the way down to Northern California.
And as long as I can remember, Portlanders have known that an earthquake is coming.
When we talk about it, we call it the big one.
This sounds kind of scary.
Because I always picture, you know, Pacific Northwest is very, like, chill.
This is the opposite of chill.
It is the opposite of chill.
So I called up a seismologist.
His name's Diego Melgar and he's the director of Crescent, the Cascadia Region Earthquake Science Center.
And I asked him, like, what would an earthquake this big feel like?
You would feel shaking where it's difficult, maybe even impossible for you to stay standing for anywhere between one or three minutes.
Start counting right now and realize how long that is.
Scientists say this earthquake, it'll demolish buildings, rupture utility lines, liquefy soil.
We might get significant collapses of bridges and any old infrastructure.
We would get thousands of landslides across the region, most of them covering major thoroughfares, especially in places that are very steep, like the coast ranges.
But Emily, even though we know so much about how this earthquake could affect us, We still know very, very little about when it's going to happen.
We don't know when?
We can't predict it at all.
One scientist I talked to.
His name is Chris Goldfinger and he's a marine geologist and paleoseismologist at Oregon State University.
He said they don't even use that word.
Prediction is sort of, in the science world, we call it the P-word.
We just don't really even speak about it because nobody can do it.
The P-word.
We don't do that in earthquake science.
And listening to this, Emily, I was like, why is that?
Right.
Why do we know so many concrete details about certain parts of this looming disaster and then zero details about this other, seemingly really crucial, part of when is it going to happen?
Today on the show the earthquake prediction problem, what we know and what we don't about quakes like the big one, and how the science is shifting under researchers' feet.
You're listening to Shortwave, the science podcast from NPR.
This message comes from WaterAid, whose mission is to change the world through water.
Imagine walking miles every day to collect water because your home has no taps, toilets or clean water.
That's the reality for one in four people worldwide.
Your support can help change the future for them.
Because WaterAid believes everything, health, food, opportunity, starts with water.
Donate to WaterAid and your gift will be matched, going twice as far to bring clean water to everyone, everywhere.
Donate at WaterAid.org slash podcast.
Support for this podcast and the following message come from Recorded Future.
Every day, millions of cyber threats compete for attention.
But only a few truly matter to your business.
As a leading threat intelligence company Recorded.
Future cuts through the noise with precision intelligence.
That's why top banks and governments trust them.
Because security leaders don't just react.
They foresee, spotting the signals that others miss, and acting before threats become setbacks.
Recorded Future.
Know what matters.
Act first.
Okay, Han, today we are talking about earthquakes and the difficulty of predicting them, which is...
Kind of scary when it comes to the magnitude 8, the magnitude 9 ones, the big ones.
But how do you know a big one is coming for the Pacific Northwest?
That's a great question.
So first, there's geologic clues of past earthquakes in the landscape.
There's what we call ghost forests, these thousand-year-old trees on the Oregon and Washington coast that seem to have been submerged in seawater really quickly.
And then in other places you can find sand deposits in the soil that must have come from big earthquakes.
And second, there's also more specific records that we have.
Human records from somewhere clear across the other side of the world, Japan.
Oh, that makes sense because Japan is extremely earthquake prone.
It sits at like the confluence of multiple tectonic plates.
Yeah, exactly.
So when a big earthquake hits there, it's often followed by a tsunami wave.
It goes like earthquake, tsunami, earthquake, tsunami.
But in the year 1700, on January 26th, Japanese scholars have all of these records of what they call the quote-unquote orphan tsunami.
Orphan because they didn't know where it came from.
It just didn't seem to have a parent earthquake preceding it.
And this tsunami arrived out of nowhere with no earthquake to go with it, no warning.
It killed a few people, destroyed some boats, and destroyed bales of rice in warehouses.
And they had written records of this.
So this is Chris again, the seismologist.
He says the Japanese records were really accurate, down to the height of the flooding and the amount of the destruction.
And using these records, it was possible for scientists to do some detective work and figure out where that big wave came from.
And so Kenji Satake, a Japanese colleague, modeled the tsunami.
You know, where did it come from?
Did it come from Alaska or Kamchatka or Chile or whatever?
And the only place that matched was Cascadia.
Which, Emily, again, is that fault line right off the Portland coast.
So...
That research is how we know that the last great earthquake in the Pacific Northwest was January 26th the year 1700, about 9 pm.
That is so precise.
It's incredible actually that they were able to track the last big one in the region to that moment in time, 325 years ago.
No, it's really cool.
And scientists have done more modeling.
They've researched earthquakes in the area further and further back.
They've talked to indigenous people who have told stories about these quakes for generations.
And they've realized that Cascadia has these really big earthquakes, usually magnitude nines every 500 years on average.
Oh, then we're fine, right?
Because if the last big one was in 1700, that's way less than 500 years ago.
So it's fine.
Right?
So this is what I thought too, but Diego told me it's not that simple.
Earthquakes can cluster in time.
So it can be that every now and then the earthquakes happen in quick succession.
So we could have a few magnitude nines only 250 years apart, then maybe a thousand year period of calm, then a quick succession of other big earthquakes.
So even though it's 500 years on average, it is not the case that they happen 500 years later.
Nothing.
Earthquake.
500 years.
Nothing.
Earthquake.
That's not how Earth works.
I wish it were.
These tectonic plates are like, we don't follow rules.
We don't observe patterns.
Yeah.
So we could be due for a major earthquake or we could be fine for the next 500 plus years.
Either or.
Okay.
Our other seismologist, Chris.
He compared it to figuring out when your Thanksgiving turkey is ready if all you did was stick it in the oven and walk away.
Somebody says, is it almost done?
Well, I don't know.
When did you turn it on?
I don't remember.
And you see the oven sitting there at 350 and you go, well, how long has it been going at 350?
I have no idea.
And you don't have a turkey thermometer either.
So you have no way of measuring when the cycle started, or how far into it you are or how cooked it is.
That sounds like how I cook.
Point is...
Earthquakes are like chaotic turkeys.
Right.
And just to complicate this a little further Emily, because I know that's what you're dying to hear we don't even know for sure that this will be a magnitude 9 earthquake.
It could be a little bit smaller, catastrophic, but not quite that big.
Okay.
But here's what we do know.
We have really good idea of what the tsunamis are going to look like and what the shaking is going to look like.
And that's actionable information that we put to use.
That's important because since earthquakes can cause tsunamis, knowing...
What different size earthquakes will do to the land, to the water, is really important for human health and safety.
Yeah, and so that's the second part of this story.
There's all of these things about earthquakes that science can and does predict, like what could happen when the big one hits.
How do scientists figure that out?
Just knowing like if it's an X magnitude earthquake, it will do this?
They look for clues from the past, and they can find those in places like estuaries and tidal marshes.
So when we have a big Cascadia earthquake, tsunami washes in sand and deposits it on these marshes.
And that sand is then preserved in the stratigraphic record.
So in the coastal sediments over time.
So this is coastal geologist and paleoseismologist Tina Dura.
She works in the geosciences department at Virginia Tech.
We actually go out there with a tube and push it down into the ground.
And, you know, the oldest earthquakes are at the bottom of the record.
And as you go up towards the surface and the sediments, you see the younger earthquakes.
And in some of these marshes, we have up to a 7,000-year record of past earthquakes.
Tina showed me a picture of one of these sediment core samples.
It kind of looks like a layer cake.
You can see the marsh dirt and then the tidal dirt on top of it, and then the tsunami dirt and then it goes all over again.
So it's like reading tree rings.
It tells the story of the geology.
What does looking at a record like that tell her?
She told me that between earthquakes, basically when there's pressure building up on these tectonic plates, it causes the land to rise which, for what it's worth, is part of the reason that climate-driven sea level rise hasn't really affected the coastlines of the Pacific Northwest the way it has say, the Gulf of Mexico, etc.
Because the land is rising along with the ocean.
It's rising at about one millimeter a year.
But of course, the next earthquake is going to reverse that.
And this land level change where it goes down is going to happen over minutes.
And it's going to cause a sudden sea level rise of up to two meters.
Combined with the already existing tsunami waves that were predicted to have, you'd get flooding, a lot of flooding, mostly in low-lying areas along the coast, the places that are flat and easy to build on, where there are already airports and fire stations and wastewater treatment plants.
And unlike other tsunamis, where the flooding comes in and then goes away, Tina said the combination of the land drop and the waves is going to mean a much more permanent change to the landscape.
So whole areas might stay flooded?
Yeah.
Wow.
And the other thing that's important to know Emily, is that This might not just affect the upper half of the West Coast.
It could also trigger another earthquake further south.
The California Big One.
So just south of the Cascadia Fault is this other tectonic plate boundary called the San Andreas Fault.
And that one's responsible for a lot of earthquakes in California.
Remember Chris Goldfinger?
He's the paleoseismologist we heard from earlier.
Yeah, the one with the incredible turkey metaphor.
Absolutely.
So in 1999, through a clerical error, he and his research team ended up sailing too far south and taking a sample of the San Andreas Fault.
And as they were comparing these samples one from the Cascadia Fault and one from the San Andreas Fault they realized that all the events that these cores recorded were happening super close together just time-wise, which is super weird, right.
So they took way more samples, they got way more data and they realized that the Cascadia and the San Andreas were what geologists call seismically linked.
They have the potential to trigger earthquakes in one another.
That sounds like a big, bad set of dominoes just, like, tipping down the West Coast.
Okay, so more flooding, more landscape change, bonus earthquakes.
Is there anything else we should know about the big one?
Like...
Is it just going to be, or are we just powerless in the face of it?
We are not.
There's good news.
Because in the past few decades, scientists have developed the technology to create an earthquake early warning system.
The idea is quite simple.
We need seismometers, sensors that feel the first teeny tiny vibrations.
Diego told me we have thousands of these little sensors located all throughout Washington and Oregon and California.
And they're all just listening to the Earth. waiting to hear these tiny, tiny vibrations.
And using decades of research and models, we know that if the teeny tiny vibrations look a certain way, then these teeny tiny vibrations are not from a five.
They're not from a magnitude six.
They're probably from magnitude eight or from a magnitude nine.
And after a few of these seismic stations detect these teeny, tiny vibrations, then all the logic, algorithms and technology kicks in and the alert goes off by cell phones, by emergency sirens and so on.
And it says, you know, earthquake, drop cover and hold on.
This entire early warning system can be activated in 15 to 20 seconds, totally automated, without any human action.
That's astonishing.
I mean 15, 20 seconds doesn't sound like a lot of time, but just even a little bit of advanced warning could be the difference between life and death, you know.
Yeah, exactly.
And all the scientists that I talked to.
They told me it's really good to know everything that we can about how this big earthquake will play out, even if we don't know exactly when it'll play out.
This is the point of the conversation at which I tell people knowledge is power.
And I'd rather know that these are the challenges we're facing, that the tsunami is probably going to be this size, that the shaking is probably going to be this intense because, armed with that knowledge, I can develop goals and objectives.
And Diego says that's the next step, right?
If you're in the Pacific Northwest, and especially if you're in a coastal town, make sure you have those goals and objectives.
Make sure you have a flooding plan.
Ask your neighbors if they have one, because When this happens, it's likely that medical experts won't be able to reach everyone, so we're going to need to rely on other people in our communities.
Find out whether your state agencies and local emergency managers have an earthquake plan, or write a letter to your legislators and ask them to push for earthquake-proof buildings and evacuation centers.
It's going to take time, but Diego told me we're making progress.
We have everything that we need to prepare.
Hannah Chin, you have repped your region well.
To get ready for this.
Thank you for bringing this to all of us.
Thank you so much for having me.
Troyvers, if you have a question about your local environment, open up your phone and record us a little voice memo about it.
You know your feelings, your thoughts, your observations and then email that voice memo to shortwave at nprorg.
We will listen and may even build an episode around your question.
Also, if you want to learn more about earthquake science and seismometers, you should check out another episode we did a while ago.
We'll link to it in the show notes.
This episode was produced by Hannah and Rachel Carlson.
It was edited by our showrunner, Rebecca Ramirez.
Tyler Jones checked the facts and Klaise Lee was the audio engineer.
Beth Donovan is our vice president of podcasting.
And special thanks to Paul Lundgren and Suzanne Carbot, whose research and expertise helped inform this episode.
I'm Emily Kwong.
And I'm Hannah Shin.
Come back for more Shortwave from NPR.
See you later.
This message comes from NPR sponsor, Capella University.
With Capella's FlexPath learning format. you can set your own deadlines and learn on your schedule.
A different future is closer than you think with Capella University.
Learn more at capella.edu.
This message comes from Capital One.
With the Spark Cash Plus card, you earn unlimited 2% cash back on every purchase for your business.
Find out more at capitalone.com slash sparkcashplus.
Terms apply.
This is Eric Glass of This American Life.
Do you know our show?
Okay.
Well, either way, I'm going to tell you about it.
We make stories that hopefully pull you in at the beginning, with funny moments and feelings and people in surprising situations, and then you just want to find out what is going to happen and cannot stop listening.
That's right.
I'm talking about stories that make you miss appointments.
This is American Life, wherever you get your podcasts.
