♪ There once was a ship that set to sea ♪ ♪ And the name of the ship was the Tommy Tommy ♪ ♪ The winds were cold, morale was high ♪ ♪ For research they'd undergo ♪ ♪ Soon may the scientists come ♪ ♪ To study the seamount off Oregon ♪ ♪ One day when the data are summed ♪ ♪ They'll predict volcano blow ♪ ♪ Deep and molten off Western shores ♪ ♪ There's mystery in its magma core ♪ ♪ Fills up tight and erupts in roar ♪ ♪ Every 5, 10 years or so ♪ ♪ Soon may the scientists come ♪ ♪ To study the seamount one on one ♪ ♪ One day when the data are summed ♪ ♪ They'll predict volcano blow ♪ - [Narrator] And that's All Science.

No Fiction.

(bright music) To talk to an instrument sitting a mile under the ocean surface, you have to speak the language.

So it's a good thing.

Michael Tepper-Rasmussen and chief scientist Bill Chadwick are fluent in chirp.

- We just sent the release code to an instrument that's been on the sea floor for the last two years.

And we're gonna get it back.

Coming up.

- Hey, it's on its way up.

- It's always nice when you get something back after throwing it in the ocean.

- [Narrator] The instrument was sitting on top of an underwater volcano about 250 miles off the Oregon coast.

It's called the Axial Seamount, and it could help us understand volcanic risk closer to home.

Half the people in the Pacific Northwest live within about 60 miles of an active volcano.

Mt.

Hood, Rainier, Three Sisters, St. Helen's and Mt.

Shasta are all considered high risk, but only one has erupted in our lifetimes.

But the Axial Seamount, it's erupted three times in the last 25 years.

More than any other volcano in the contiguous United States.

- Volcanoes are always gonna be a bit mysterious.

You know, all you see on land is the surface, but you know all this stuff is happening underground.

It's all a detective story of trying to figure out what's gonna happen next at the surface.

- [Narrator] Axial sits on the Juan de Fuca Ridge where two tectonic plates are spreading apart.

- There's volcanic activity all up and down the ridge, and that's where new sea floor is created by eruptions.

- [Narrator] Axial doesn't blow its top when it erupts.

Instead, the magma below causes it to crack open on its slopes and ooze lava.

- You know, in general, I think we learn the most about how volcanoes work by studying them in the the act of doing something.

- [Narrator] With the help of Jason, a remotely operated submarine, the science team is trying to figure out how to predict volcanic eruptions on the Axial Seamount months or even years in advance.

♪ The work was done by a sub named Jason ♪ ♪ It circled around the caldera basin ♪ ♪ And searched for signs of deformation ♪ ♪ That signaled sea floor grow ♪ ♪ Soon may the scientists come ♪ ♪ To study the seamount off Oregon ♪ ♪ One day when the data are summed ♪ ♪ They'll predict volcano blow.

♪ (acapella singing) - A big component of our research is trying to understand what triggers eruptions.

And then hopefully we can learn enough about these systems, we can then start to look at other systems that might pose more of a hazard for people.

- [Narrator] Nooner and Chadwick predicted the 2015 Axial eruption about seven months in advance.

- This was the first accurate volcanic eruption forecast on the planet based off ground deformation data alone.

So they won't tell you that, but it's pretty cool.

- [Narrator] Now they're trying to figure out what Axial will do next.

- Oh yeah, here's a fissure.

This is kind of a natural laboratory where we can make forecasts without worrying about if it's gonna be a false alarm and anybody's gonna care.

You know?

(chuckling) - [Narrator] Leading up to the eruption of Mount St. Helens, fear of false alarms added to the challenge of preparing nearby communities for the eruption.

- [Bill] Here there's just a bunch of tube worms and octopuses on the sea floor.

And they don't care.

- [Narrator] To make these predictions, they need to understand what's happening inside the volcano.

Which means slowly traveling around the caldera collecting and deploying their sensors.

(adventurous music) - [Scott] Kind of amazing when you stop to think about it.

We're able to send a vehicle down and find the exact tiny little spots every time we come out here.

- [Narrator] Their research tools of choice to study Axial are bottom pressure recorders.

The pressure recorders were originally designed to detect tsunamis.

But Chadwick and Nooner have worked to repurpose them to precisely measure changes in the height of the sea floor.

- Let's say leading up to an eruption the amount of magma in the magma chamber is increasing, and so the surface responds by moving up.

It swells.

It inflates kind of like a balloon.

- [Narrator] It's a little counterintuitive, but the more the bottom rises the less water it has on top of it.

And the less water there is pressing down, the lower the water pressure on the ocean floor.

By collecting data year after year, they can track changes in the volcano.

- Get multiple cycles of eruption, which is really powerful when you're trying to understand what's going to happen in the future.

- [Bill] So this is lava that erupted in 1998.

- [Narrator] Jason and its pilots are masters of precision, manipulating the instruments being used to study Axial.

- [Bill] So he is really driving with his mind.

It's like a Jedi mind trick.

- [Tito] All right, we're gonna go back down to the bottom.

Take a look.

- [Bill] Okay.

- [Narrator] But sometimes the local residents of the volcano make their jobs difficult.

Meet the deep sea spider crab of Axial Seamount.

It's one of the more curious residents of the volcano.

- [Bill] Oh, there's a crab on the instrument.

That sucker's big.

- [Narrator] The crab has taken up residence on a seismometer that's definitely sensitive enough to pick up the tippy taps of crab feet.

So it has to go.

- [Bill] I didn't put the crab into my dive plan.

(dramatic music) - [Narrator] They settle on using the sub's vacuum hose called "the slurp".

- [Bill] Turbo.

We want turbo suck.

- [Narrator] But the crab has other ideas.

- [Bill] My new condo.

- [Narrator] So the claw comes out.

- [Tito] That's for you, buddy.

(scientists laughing) ♪ Soon may the spider crab come ♪ ♪ To tap seismometer like a drum ♪ ♪ One day when the science is done ♪ ♪ He'll have undersea condo ♪ - [Narrator] The main lab is the beating scientific heart of the research ship, and the scientific work continues around the clock.

- So if these look good, we tend to tend towards keeping them as is.

- It's where the BPRs recovered from the ocean floor come to reveal their secrets.

- It's a humble looking instrument, but very powerful in what it can record, for how long, and the sensitivity of it.

- [Narrator] But this instrument has spent most of its life, in the high pressure, near freezing, corrosive world of the deep ocean.

Powered only by a small battery pack- - Please wake up.

- I'll try reconnecting it.

- [Narrator] There's a lot that could go wrong.

- It should be continuously recording for two years.

This is always the moment of truth, 'cause that's the data.

669 files.

Which is a very good sign.

- [Narrator] The data is intact, increasing the likelihood that the researchers will be able to forecast the next eruption.

- So yeah, that's Axial caldera right there.

- [Narrator] But given what they know about the current temperament of Axial, that eruption is still several years away.

Maybe.

- If you think you know what's going on, nature will usually make you humble, humbler, by doing something you didn't expect.

- [Narrator] But with three eruptions already under their belts, they're closer than they've ever been before to understanding what makes Axial tick.

(acapella singing) - Good.

- [Narrator] OPB members are the magma chamber to our volcanic seafloor.

We rise with your support.

Thanks.

- I don't know if I'm surviving if I get in the water.

- [Narrator] And don't miss out on any of OPB's great science, environment, arts, history and food programs by subscribing to OPB Insider at opb.org/allscience.