News / Science & Technology

Simulated Disasters Provide Earthquake Data

Models could help save lives

Lamont Research Director Heather Savage prepares a machine in the Rock Mechanics Laboratory that will simulate earthquake conditions on a micro-scale.
Lamont Research Director Heather Savage prepares a machine in the Rock Mechanics Laboratory that will simulate earthquake conditions on a micro-scale.

Multimedia

Audio

Earthquakes are among the most devastating and frequent natural disasters on the planet - and also among the least understood.

Scientists at Columbia University’s Lamont-Doherty Earth Observatory, about 30 kilometers north of New York City, are working to change that.

Quake dynamics

The Rock Mechanics Laboratory is one of several specialized labs at Lamont-Doherty’s Division of Seismology, Geology and Tectonophysics, now studying the subterranean dynamics of earthquakes.   

Research professor Heather Savage fires up a machine that simulates, in miniature, real earthquake conditions - the rubbing, slipping and sliding of the Earth’s massive plates, generating data for analysis.

“So what we do here in our lab is put two pieces of rock that we’re interested in, say two pieces of granite, and then we put them under stress, and then load them and load them and load them until they want to slide," Savage says. "And then we look at things like how much stress did we have to put on those rocks until they started sliding? And that tells us something about how strong that fault surface is. And that tells us something about how much stress a fault in nature can take before it starts having an earthquake.”

Significant differences

Savage acknowledges there can be significant differences between the highly controlled mini-quakes she generates in her laboratory and those that occur in nature.

“The problem comes in when you start to think of how complex fault zones really are. They are much bumpier than that, which can completely change your distribution of stress on the whole fault. And as soon as you start to slide things past each other, you start to break some of that roughness up and create little particles. And now your fault is no longer two pieces of rock touching each other. Now it’s got a layer of what we call ‘gouge’ in between, which is all those busted up particles of your original two surfaces. Now you’re talking about the strength of a granular material. And that opens up a whole new branch of physics which is also not well understood and that is the behavior of granular material. So there are lots of interesting things that go on in faults and a lot of different sciences that get pulled in.”

Many of those sciences are the focus of the other labs at Lamont-Doherty Earth Observatory. Geo-chemists, for example, analyze the temperature and molecular properties of the Earth’s material. Physicists can help answer questions about how earthquake aftershocks work.

Tremors

For example, when plates shift or bump against each other, why isn’t there one massive shudder followed by complete rest once the tension has been relieved, rather than the series of smaller, potentially dangerous tremors that follow the collision of plates?

One answer lies in the fact that the initial major quake only relieves some of the pent-up energy between two opposing plates. So called “aftershocks” just finish the job, as when a rock slides down a mountain, comes to rest, and is jolted into continuing its downhill course.

Another reason for aftershocks are the “seismic waves” that earthquakes generate, which Savage likens to what happens when you jiggle the end of a loose metal spring.      

“If you just tweak that spring, just give it a little push, you can watch a wave travel from where I pushed it and it will end up at you and then a smaller wave will come back at me, and so forth, depending on how hard I pushed it.”  

Much of the seismological work at Lamont-Doherty is more practical than theoretical. For example, the global network of digital seismic monitoring stations it helps to manage enables scientists and governments around the world to be alerted almost immediately when an earthquake occurs.

Because the digital information travels through cyberspace faster than seismic waves propagate through the earth, people can sometimes be warned before a quake strikes their local areas.  

Scientists might never be able to predict the when and where of particular earthquakes. But Lamont Doherty seismologists are also working to develop mathematical earthquake probability models. The models could save lives by giving government leaders and urban planners a more accurate picture of the earthquake risk in any given area.

You May Like

Computer Crash Halts US Visa, Passport Operation

Problems with database have resulted in extensive backlog of applications, affected State Department's consular offices all over the world More

Migrant Issues Close to Home Spur Groups to Take Action

Groups placing water, food in the desert, or aiding detainees after release, have one common goal: no more deaths of migrants crossing illegally into the US More

World Bank: Boko Haram Stalls African Aid Projects

Islamist group’s terrorism sets back agriculture, health efforts in Cameroon, Chad and Nigeria More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Israel Targets Gaza Supply Tunnelsi
X
July 24, 2014 4:42 AM
The Israeli military has launched a ground operation in Gaza to destroy the myriad tunnels that may have been used to smuggle weapons to Hamas. VOA's Zlatica Hoke reports that could mean more hardship for the people of Gaza, who obtain some of their essential supplies through these underground passages
Video

Video Israel Targets Gaza Supply Tunnels

The Israeli military has launched a ground operation in Gaza to destroy the myriad tunnels that may have been used to smuggle weapons to Hamas. VOA's Zlatica Hoke reports that could mean more hardship for the people of Gaza, who obtain some of their essential supplies through these underground passages
Video

Video MH17's 'Black Boxes' Could Reveal Crash Details

The government of Malaysia now has custody of the cockpit voice and flight data recorders from Malaysia Airlines Flight 17, which was hit by a missile over Ukraine before crashing last week. As VOA's Carolyn Presutti reports, the so-called black boxes may hold information about the final minutes of the flight.
Video

Video Living in the Shadows Panel Discussion

Following a screening of the new VOA documentary, "AIDS - Living in the Shadows," at the World AIDS conference in Melbourne, a panel discussed the film and how to combat the stigma associated with HIV/AIDS.
Video

Video IAEA: Iran Turns its Enriched Uranium Into Less Harmful Form

Iran has converted its stockpiles of enriched uranium into a less dangerous form that is more difficult to use for nuclear weapons, according to the United Nations’ Atomic Energy Agency. The move complies with an interim deal reached with Western powers on Iran's nuclear program last year, in exchange for easing of sanctions. Henry Ridgwell reports for VOA from London.
Video

Video Relic of Saint Draws Catholics Worried About Immigration Issue

A Roman Catholic saint who is a figure of devotion for those crossing the border into the United States is attracting believers concerned about the plight of undocumented immigrants. Mike O'Sullivan reports from Los Angeles, where a relic of Saint Toribio has drawn thousands to local churches.
Video

Video US Awards Medal of Honor for Heroics in Bloodiest of Afghan Battles

U.S. combat troops are withdrawing from Afghanistan, on pace to leave the country by the end of this year. But on Monday, U.S. President Barack Obama took time to honor a soldier whose actions while under fire in Afghanistan earned him the Medal of Honor. VOA's Jeff Seldin has more from the Pentagon.
Video

Video Ukraine Rebels Surrender MH17 Black Boxes

After days of negotiations, a senior separatist leader handed over two black boxes from an airliner downed over eastern Ukraine to Malaysian experts early Tuesday. While on Monday, the U.N. Security Council unanimously demanded that armed groups controlling the crash site allow safe and unrestricted access to the wreckage.
Video

Video In Cambodia, HIV Diagnosis Brings Deadly Shame

Although HIV/AIDS is now a treatable condition, a positive diagnosis is still a life altering experience. In Cambodia, people living with HIV are often disowned by friends, family and the community. This humiliation can be unbearable. We bring you one Cambodian woman’s struggle to overcome a life tragedy and her own HIV positive diagnosis.

AppleAndroid