<http://schema.org/articleBody>
"  A NASA-led research team may have come one step closer to accurately predicting the size of earthquake-induced tsunamis. Tsunamis are generated when an earthquake or underwater landslide displaces a large amount of water; only when that displaced water reaches shore does it turn into large waves. When an 8.8-magnitude earthquake struck off the coast of Chile on Feb. 27, scientists predicted that waves as high as 12 feet could hit Hawaiian shores; only 12-inch waves actually materialized. &amp;quot;Magnitude is just a proxy for how big [an earthquake] is,&amp;quot; says Brian Shiro, a geophysicist at NOAA&amp;#039;s Pacific Tsunami Warning Center. &amp;quot;It&amp;#039;s tough to say how that translates to movement on the seafloor.&amp;quot;  Because of the sheer size of the earthquake, Shiro says, a Pacific-wide warning was issued right away, before the typical models that predict the size of a tsunami\u2014which use combined readings from deep ocean monitoring buoys and shore-based sea-level gauges\u2014could even be run. (Hawaii residents completely evacuated to higher ground.) The first models predicted the 12-foot waves; a second model, obtained when more data became available, was right on at 12 inches, Shiro says. A prototype detection system developed by scientists at NASA&amp;#039;s Jet Propulsion Laboratory more accurately predicted the size of the tsunami much more quickly, without the need for buoy feedback. The system used data from JPL&amp;#039;s Global Differential GPS (GDGPS) network, which measures the ground movements\u2014down to a few centimeters\u2014of hundreds of regional and local GPS sites every second. The method allows scientists to estimate the amount of energy an undersea earthquake transfers to the ocean to create a tsunami.  The ground motion of the Feb. 27 quake was captured by a GDGPS station 146 miles from the quake&amp;#039;s epicenter. Based on the GPS data\u2014provided to scientists within minutes of the quake\u2014the system predicted that a moderate local tsunami would be generated by the quake, with minimal effects in the Pacific; the result was confirmed using sea surface height measurements from altimetry satellites.  &amp;quot;This successful test demonstrates that coastal GPS systems can effectively be used to predict the size of tsunamis,&amp;quot; team leader Y. Tony Song said in a press release. &amp;quot;This could allow responsible agencies to issue better warnings that can save lives and reduce false alarms that can unnecessarily disturb the lives of coastal residents.&amp;quot; Yoaz Bar-Sever, manager of the GDGPS system, says that scientists were fortunate to have a station close to the epicenter, which helped them get accurate results quickly. &amp;quot;Broad international collaboration is required to densify the GPS tracking network,&amp;quot; he said, &amp;quot;so that it adequately covers all the fault zones that can give rise to large earthquakes around the world.&amp;quot; NOAA&amp;#039;s deep ocean buoys and shore-based sea-level gauges are no longer the most accurate tsunami-detectors in town. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/science/environment/a5867/earthquake-tsunami-prediction/>