How Underwater Telecom Cables Could Help Detect Tsunamis

ARIELLE DUHAIME-ROSS: This is Science Friday. I’m Arielle Duhaime-Ross. If you live in a coastal place like I do, there may be a nagging thought at the back of your mind what if there’s an earthquake and then a tsunami. Tsunamis are scary because they can happen really fast, and every minute counts when you’re trying to get to higher ground.

So having an Early Warning System in place really could save lives. One promising way to detect tsunamis as early as possible is the use of underwater cables, tapping into existing telecommunication cables that crisscross the bottom of the sea. And Portugal, which was hit by a pretty famous tsunami in 1755, is about to be the test site for this project.

Joining me now to talk about this is the chair of the UN’s Joint Task Force on Smart Subsea Cables. Dr. Bruce Howe, Research Professor in Ocean and Resources Engineering at the University of Hawaii at Manoa. Dr. Howe, welcome to Science Friday.

BRUCE HOWE: Thank you for having me.

ARIELLE DUHAIME-ROSS: Thank you so much for being here. So explain to me how this Early Warning System works. It’s my understanding that there’s a wide underwater network of telecommunications cables. That’s how we get our internet.

And they’re already there. But the idea behind this project is to take these cables and make them part of this system. So how is that going to work?

BRUCE HOWE: Well, the basic idea is to integrate underwater sensors into new cables that will be deployed over the next years and decades. There are between 1 and 2,000,000 kilometers of cable out there now, operational, and it’s always being replaced, about 10% per year. And so there’s plenty of opportunity to do this.

ARIELLE DUHAIME-ROSS: OK. So tell me about these cables. What kind of technology is going to be integrated into these cables?

BRUCE HOWE: There will be three sensors for temperature, ocean bottom pressure, and seismic motion. So for tsunami purposes, it’s really the pressure that measures the actual in water wave of the tsunami. And then the seismic sensor actually measures typically the earthquake that causes the tsunami and provides early warning from the earthquake point of view as well.

ARIELLE DUHAIME-ROSS: OK. So in a nutshell, how could these boosted cables detect tsunamis and earthquakes early?

BRUCE HOWE: Yeah. So in Cascadia, the expectation is that the earthquake, the big earthquake that will come at some point, is about 100 kilometers offshore, on that order. And so if the cable is close to that, or closer than 100 kilometers, it’s closer than any shoreside instrument. And therefore, it can give faster warning of any event it detects. And if the cable is still closer to the trench, the subduction zone trench that causes the earthquake, it can give significantly more early warning.

ARIELLE DUHAIME-ROSS: So let’s just say there’s an earthquake. Tell me what the cable will detect and at what point it’ll go, OK, I got to send out a ping, like this is bad.

BRUCE HOWE: Well, the data comes ashore in real time, instantaneously effectively. But the first indication is one type of earthquake wave called a P wave, and that propagates relatively quickly. So it’d take, for instance, 20 seconds, let’s say, to get to shore.

And so this could detect it within a few seconds and give that early warning. And then the next wave that comes in is a shear wave, it’s called. And that actually produces most of the damage and that travels more slowly and would reach shore in a minute or so.

So that’s the first indication. And then, at the same time obviously, the movement of Earth will create a water wave and that travels much slower. And it would take on the order of 20 minutes, let’s say, to get to shore. So there’s both like a minute or so of extra warning for earthquake purposes and then on the order of 20 minutes or so for the tsunami wave.

ARIELLE DUHAIME-ROSS: OK. And what kind of improvement is that compared to how we currently do things?

BRUCE HOWE: Well, right now there are only a couple of dart buoys offshore. These are buoys with bottom pressure sensors, but no seismic sensors. And there are, I’m not sure, two or three just off Washington, Oregon. So they’re very sparse and somewhat farther off shore.

In the case of Oregon and Washington, there is already a scientific cable system there called the Ocean Observatories Initiative. And there are some seismic and pressure sensors out there, but they’re not really connected in an operational sense yet.

ARIELLE DUHAIME-ROSS: OK. So this is really going to be sort of a different way of doing things. This is a big leap forward in your mind?

BRUCE HOWE: Yes. Because the main thing is it’s coupling the scientific and early warning aspects with commercial telecom cables. And so, yes, we’re hoping and working towards having a cable offshore Washington, Oregon, probably one that goes to Japan, for instance, and goes by the Aleutian Trench, which generates really big earthquakes and tsunamis. The overall goal of the project is to have global distribution, not just off the US. And so it’s only affordable through joining forces with the telecom industry and riding piggyback, basically, on their cables.

ARIELLE DUHAIME-ROSS: Got it. And this really is an international project, right? It’s starting– the pilot project is happening in Portugal. Why Portugal? Tell me about that.

BRUCE HOWE: Well, I mean the fundamental reason was they had an old cable that was getting too old, both technically and end-of-life kind of thing, 25 years. And so they had to replace it. And so the regulatory agency of Portugal for telecommunications was tasked with the job of planning this.

And from the very first day, the director mandated that it shall have environmental sensing and what they call seismic detection because of the 1755 earthquake. So from the very start of the project in 2018, the planning, it was a smart cable.

ARIELLE DUHAIME-ROSS: Got it. Right. Because what happened in 1755 really was devastating for Lisbon, right?

BRUCE HOWE: Lisbon and the whole coastline of Portugal and Spain and North Africa as well.

ARIELLE DUHAIME-ROSS: So when it comes to earthquakes and tsunamis, what can a few extra minutes do in terms of helping people survive?

BRUCE HOWE: The saying is with the earthquake, you duck under a table to protect yourself for the minute or so of the earthquake, hopefully only that long, maybe several. But survive long enough so that then you can run uphill. Presumably you know a tsunami evacuation route, and/or go up vertically if you’re in a building that’s suited for that purpose. So that’s the main thing is give you time to save your own life during the earthquake phase and then take action to escape.

ARIELLE DUHAIME-ROSS: Get to higher ground.

BRUCE HOWE: Exactly.

ARIELLE DUHAIME-ROSS: Right. Right. So it really is imperative that we have a better system in place.

BRUCE HOWE: Yes.

ARIELLE DUHAIME-ROSS: Are there other specific parts of the world where these smart cables could be most useful? What regions of the world are most at risk for tsunamis?

BRUCE HOWE: Wherever these subduction zones occur, where ocean crust dips down under a continent, typically. So it’s the whole Pacific rim of fire from Southern Chile all the way up around our West Coast Aleutians, down past Japan, and all the way down to New Zealand, and even Antarctica, you could say. So those are the main regions where large earthquakes occur and result in tsunamis as well.

ARIELLE DUHAIME-ROSS: Got it. And so the goal really is to make this a worldwide network.

BRUCE HOWE: Yes. And it’s not just for earthquake and tsunami early warning, but it’s also for climate. So there’s temperature measurements and the pressure is a measure of ocean circulation as well. So it’s very important from a climate perspective as well.

ARIELLE DUHAIME-ROSS: Huh. So what are the hurdles to installing more of these boosted cables around the world? It seems sort of like a no brainer to get them everywhere. And at the same time, I would imagine that there’s a cost. And because this is an international project, I don’t know who’s paying for this. So how hard is it to make this stuff happen?

BRUCE HOWE: Well, we’ve been at it 14 years. And we’re having our first successes now. Yes, money is the main issue for Portugal. It’s all government funded.

But with support from the European Union, the total project’s around 150 million Euros and the European Union is putting in 40 million for connectivity purposes. And then there’s a second system going in roughly the same time called Tam-Tam between Vanuatu and New Caledonia. And there the French government is supporting a large portion of it, and then commercial company is putting in the rest.

ARIELLE DUHAIME-ROSS: So if it’s proven that the project in Portugal works well, do you think other countries will show more interest and also get on board and be willing to pay for this?

BRUCE HOWE: We expect great things from those two projects setting precedents and demonstrating that there are many problems. There’s money. There’s technical proof. There’s permitting issues, legal issues, security issues. And so these first two address many of those concerns and will set valuable precedents.

ARIELLE DUHAIME-ROSS: I do want to ask you one question here, when an earthquake gets detected, and then there’s an idea, OK, there could be a tsunami here, how do I as an average resident of a coastal area, how do I then get that message?

BRUCE HOWE: Well, in the United States, there is a warning system. And in many places–

ARIELLE DUHAIME-ROSS: You mean like the Amber Alert System, right? Those emergency–

BRUCE HOWE: Exactly.

ARIELLE DUHAIME-ROSS: –type messages that you get on your phone?

BRUCE HOWE: Exactly. And sirens, I mean, here in Hawaii we have sirens all over. And I think along parts of Oregon, Washington, there are also sirens.

And there’s a program called Tsunami Ready. So there are training exercises in public schools, for instance. They actually do an evacuation.

ARIELLE DUHAIME-ROSS: How will things work in Portugal?

BRUCE HOWE: They have the same thing in place, too. So they have an early warning system in place, and it’ll be augmented. And hopefully, this will catalyze more investment to make it even better.

ARIELLE DUHAIME-ROSS: Got it. OK. You’ve been working on smart cable technology for decades now. So much of your life has been dedicated to this. What’s it like to finally see it coming to fruition in Portugal?

BRUCE HOWE: Well, it’s wonderful. I was just there last week. And I think everyone is really enthusiastic. And they’re really gearing up to implement it. And also, they recognize that they are the first adopters and have a responsibility to demonstrate to the rest of the world and take a leadership role in this to try and promote it elsewhere as well.

ARIELLE DUHAIME-ROSS: All right. Well, I wish you luck. That’s all the time we have for now. Thank you so much for your time. I really appreciated this conversation.

BRUCE HOWE: Thank you. I appreciate it.

ARIELLE DUHAIME-ROSS: Dr. Bruce Howe, Research Professor in Ocean and Resources Engineering at the University of Hawaii at Manoa.

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