NASA, Scripps Institution of Oceanography Shake-up Earthquake Warning Systems

The fault lines running beneath California’s clay, sand and loam are rarely visible, and yet never far from mind for the tens of millions of people who call the state home. Even before California’s next major quake hits, its implications are already reverberating through research and first responder communities.

When disaster strikes, the quality of the response—and therefore the number of lives saved—usually comes down to this: how good is the information you’re working off? And how quickly can you get it?” explained Rusty Sailors, the chief executive officer of LP3, a security firm, and an experienced first responder.

The most important information that is immediately needed for earthquake disasters is the location, depth, and magnitude of the earthquake. Despite the devastation that earthquakes—and the tsunamis they cause—continue to wreak, the methods of quickly determining an earthquake’s magnitude remain insufficient. The most common method of establishing an earthquake’s magnitude is using seismic sensors on the ground that measure the shaking of the earth’s crust.

“The problem with this is,” explained Dr. Yehuda Bock from the Scripps Institution of Oceanography, “the magnitudes based on seismic data becomes less reliable at the upper end of the register. In other words, one can erroneously calculate that the magnitude of an earthquake will be an 8.0 instead of a 9.0, although a 9.0 is about 30 times more severe.” Getting a more accurate magnitude calculation using only seismic data for earthquakes takes time, often upwards of 20 to 25 minutes for the largest earthquakes. As a result, initial response efforts are often guided—and at times misguided—by preliminary analysis that tend to underestimate the earthquake’s magnitude.    

“With the 2011 earthquake in Japan,” Bock continued, “they used seismic data alone to estimate the earthquake’s magnitude—and they underestimated it.” Underestimating the magnitude of an earthquake can mean that too small of an area receives hazard warnings, that those who receive the warning are under-prepared for the actual event, and that authorities will likewise underestimate the tsunami hazard zone. “So even if they did everything right after underestimating the magnitude—the tsunami modeling, the hazard zone mapping, giving directions to evacuation routes—they were still moving people out of a hazard zone that was way too small,” Bock explained. “There were a lot more casualties because of that.” 

Authorities and first responders need better data to accurately and quickly assess the risk associated with the earthquake. Bock, in collaboration with NASA’s Jet Propulsion Laboratory, looked to space.

Traditional seismic measurements enable researchers to measure one of the two ways that the earth moves during an earthquake: the dynamic shaking of the ground. There is also a second type of movement: the permanent displacement of the earth after the earthquake. The latter of these is responsible for the all too familiar images of roads and sidewalks bisected and no longer fully aligned. Bock and his colleagues sought to improve earthquake magnitude measurements by collecting data on the permanent displacement at GPS sites and marrying them with seismic measurements.

“GPS technology had been around for awhile,” Bock said, referring to the satellite-based navigation system that now is commonly used in cars, smart phones and even some watches. A challenge with GPS data, however, has been its accuracy. GPS measures the location of a sensor on the ground by calculating how long it takes for a satellite transmission to reach the ground. The accuracy of that data, however, depends on how much water vapor it passes through in the atmosphere along the way.

“NASA saw the potential, and had the know-how, to take GPS to the next level to help provide more accurate and timely information,” Bock said. To enhance the accuracy of GPS data, NASA’s Jet Propulsion Laboratory and Scripps Institution of Oceanography have upgraded scientific GPS stations with sensors that monitor for earthquakes while collecting GPS, pressure, temperature and seismic data in real-time across southern California. The weather data is used to account for the water vapor that the GPS signal travels through, thereby enhancing the accuracy of the GPS data. The stations then send the information to Scripps via the internet and radio waves—which travel faster than shock waves—where scientists use the GPS data to measure exactly where and by how much the ground moved during an earthquake. The GPS data are then inputted into computer models to estimate the earthquake’s location, magnitude, depth, and tsunami potential. This can all happen within minutes, enabling rapid and more accurate earthquake data than ever before.

“I look forward to the day when these alerts will become immediately available to first responders—right to their trucks and battalion chiefs,” Sailors said. “Yehuda [Bock] is really passionate about ensuring this information gets into the hands of the people who need it most. We’ll get there.”

“If only they had implemented something like this in Japan in 2011,” Bock said. He recognizes the lives that could have been saved if tsunami modeling there had been based on more accurate and rapid earthquake magnitude data; and he—along with his NASA colleagues—want to ensure that this new earthquake technology is in the hands of the California emergency response community.

NASA is beginning to work with NOAA‘s Tsunami Warning Centers to evaluate NASA’s new technology at NOAA for use in their tsunami early warning system. There are also plans to expand the geographic reach of these technologies, so that they will one day span the Pacific Rim. The possibilities are, of course, global.

As with all innovations, there is already an unforeseen opportunity to apply this technology. The GPS-enhanced earthquake stations are being installed on buildings—such as hospitals, bridges and skyscrapers—to determine, after an earthquake hits, how far the building permanently traveled through a shift in the earth’s crust. This information will enable authorities to more effectively and quickly “tag” buildings as safe, temporarily dangerous or condemned.

“The only way to address natural disasters today is to get high enough to really see what’s going on,” Bock said. “NASA gives us this.”

Those involved in the project hope a major quake will never strike and put these technologies to the test. Bock, Sailors, NASA and many others, however, are breaking ground now to help safeguard as many lives as possible in case California experiences another major earthquake.

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Collapsed and burned buildings shown at Beach and Divisadero in the Marina District, San Francisco. Click on image to enlarge. Credit: USGS, C.E.Meyer

For more information about NASA’s Space Geodesy Project, visit: http://space-geodesy.nasa.gov/

Rob Garner:  Washington D.C. Metro Area – ‎Lead Web Editor for NASA Goddard’s Office of Communications – ‎NASA Goddard Space Flight Center

Republished from NASA

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