By Clay Dillow Posted 04.23.2012 at 5:20 pm 5 Comments

The Devastation Following the March 2011 Tohoku Earthquake and Tsunami U.S. Navy

When the Tohoku earthquake struck Japan in March of last year, seismometer data allowed authorities to issue earthquake earnings within eight seconds of first realizing something was seismologically amiss. But their initial readings were not fully accurate, labeling the ‘quake a magnitude 7.1. It took authorities another 20 minutes to revise the magnitude to its real value of 9. Just ten minutes later, the tsunami hit.

Researchers at NASA and a group of universities think they can issue more accurate readings faster using global positioning data, thus allowing officials to more accurately assess risks and issue better-informed warnings up to ten times faster. They are currently testing a system via hundreds of GPS receivers that dot the Pacific Northwest, providing realtime measurements of ground movement in the Cascadia subduction zone, the tectonic region there with the potential to produce magnitude-9 ‘quakes. When the ground literally moves within the zone covered by the GPS receivers, that location data reaches the lab in just a tenth of a second.

That allows researchers to fix the location of the epicenter within about half a second, and can give researchers dozens of seconds of notice before seismic waves make it to a populated area, depending on the location of the epicenter. Those handful of seconds aren’t so helpful when it comes to issuing earthquake warnings. But in the case of a strong earthquake that could spawn a devastating tsunami like that triggered by the Tohoku event, this quick characterization of the earthquake could save lives.

Related Articles

'Quake Catcher' Software Converts Laptops Worldwide into Earthquake Sensor Network
Indonesia's New Tsunami Warning System
The Atmospheric Signature of the Japan Tsunami Could Help Develop a Space-Based Warning System

Tags

Science, Clay Dillow, earthquakes, environment, geology, nasa, seismology, tsunami warnings, tsunamis
The reason: seismometers are great at accurately fixing a value to small earthquakes. But they have trouble distinguishing between, say, a magnitude-7 and a magnitude-8, and even more trouble the higher you go up the scale. This is partially because big quakes may shake the terrain for longer rather than harder. And its a problem that GPS doesn’t really have to deal with.

By measuring the actual movement of the ground during an earthquake event via GPS, scientists can quickly and accurately define the magnitude of the earthquake, and of any aftereffects it might cause, like tsunami. In the case of Tohoku, the seismologists had underestimated the magnitude of the quake by nearly two full points. That means the early tsunami warnings that went out didn’t account for the full potential of the tsunami risk.

Using the Tohoku earthquake data as a model, the NASA/university research team nailed the true magnitude in just two minutes--ten times faster than the seismometer data in Japan allowed back in March 2011. With faster and more accurate earthquake assessments, authorities can issue better warnings for associated threats like tsunamis--and hopefully that ten-fold savings in time can translate to lives saved. More on this over at Nature.

[Nature]

5 Comments

Link to this comment
shutterpod
04/23/12 at 6:50 pm

Worldwide, it should be illegal to build anything that can wash away near a land-ocean interface. For insurance reasons, and reasons related to damage of the sea and all it contains, building near a coastline should be banned.

We have Japanese flotsam coming ashore in Washington state, and hundreds of tons more just floating around the gyre and elsewhere.... for what? Because people want to live RIGHT ON the water's edge?

Despite ALL of their losses due to the tsunami, Japan should have been internationally fined for the pollution it allowed to happen.

Link to this comment
chriscloo
04/23/12 at 11:24 pm

Well in that case lets sue all the people in the world why don't we, we live on a planet with 70% water so we all help in its pollution.

Shutterpod, that is how you sound, the Japanese have lived there for hundreds if not thousands of years and have done well on it despite the population they have and the size of their islands. They also have the issue that the island has almost no resources to speak of, their main resource is their fish. The islands also are literally washing away with every passing day...its just a large pile of sand, so maybe when their ancestors settled there it was part of china and not anywhere near the ocean.
I also notice how you don't complain about the US's pollution or any one elses...in fact you make it seam like all the pollution on earth is their fault not ours. I could write a paper on this but I will be nice and stop here...so Either get your facts straight or don't post about what you don't know!

Link to this comment
Khaelmin
04/24/12 at 8:03 am

@shutterpod, are you out of your freaking mind? By this logic we should have sued Iceland for the pollution caused by the ash plume that came out of their volcano last year. Why the hell didn't they drill shafts in the side of the mountain to relieve the pressure inside the volcano? Oh, the money lost due to airplane delays over Europe!

Also, how heartless are you to demand that a nation already wracked by such a disaster be fined? That's right, the money for rebuilding and aiding the victims would be better used to pay for fines. Please, kill yourself, maybe you'll find some humanity in the next life.

Anyway, back on topic, this is a great use for the GPS satellites. The more warning, the better.

Link to this comment
Robot
04/24/12 at 8:10 am

Japan has these small statues posting the high marks of past Tsunami. The people built past these marks and so part of the reason we have the devastation of the Tsunami. We do the same thing often with airports in USA. As time passes we tend to forget the hazards of the past and stop being careful.

.............................
Science sees no further than what it can sense, i.e. facts.
Religion sees beyond the senses, i.e. faith.
Open your mind and see!

Link to this comment
shutterpod
04/25/12 at 4:11 am

I didn't complain about ALLLLL the other coast pollution because THIS article is related to the Japanese tsunami.

Yes, when Katrina hit New Orleans, the government should have made the city be removed from its place, forever.

Mankind needs to start living up to his oh-so-high estimation of himself as the dominate life-form on this planet, and start giving a shit about his dominion.

Don't shit where you eat.


140 years of Popular Science at your fingertips.



Popular Science+ For iPad

Each issue has been completely reimagined for your iPad. See our amazing new vision for magazines that goes far beyond the printed page



Download Our App

Stay up to date on the latest news of the future of science and technology from your iPhone or Android phone with full articles, images and offline viewing



Follow Us On Twitter

Featuring every article from the magazine and website, plus links from around the Web. Also see our PopSci DIY feed


April 2013: How It Works

For our annual How It Works issue, we break down everything from the massive Falcon Heavy rocket to a tiny DNA sequencer that connects to a USB port. We also take a look at an ambitious plan for faster-than-light travel and dive into the billion-dollar science of dog food.

Plus the latest Legos, Cadillac's plug-in hybrid, a tractor built for the apocalypse, and more.


Online Content Director: Suzanne LaBarre | Email
Senior Editor: Paul Adams | Email
Associate Editor: Dan Nosowitz | Email
Assistant Editor: Colin Lecher | Email
Assistant Editor:Rose Pastore | Email

Contributing Writers:
Rebecca Boyle | Email
Kelsey D. Atherton | Email
Francie Diep | Email
Shaunacy Ferro | Email

circ-top-header.gif
circ-cover.gif