Lawson. Like the NOAA Deep-ocean Assessment and Recording of Tsunamis (DART) buoy, the SAIC Tsunami buoy (STB) is made up of three components, a surface communications buoy component, a bottom pressure recorder component and a buoy mooring component. A tsunami detection buoy measures small changes in the depth of the deep ocean caused by tsunami waves as they propagate past the sensor. This is accomplished with an extremely sensitive bottom pressure sensor/recorder measuring very small changes in pressure as the waves move past the buoy. In the deep ocean, tsunamis have wavelengths that can exceed 120 miles long with amplitudes of only several inches; so typically a ship won't notice them as they pass by at speeds that can approach 500 mph. The bottom pressure recorder component includes a processor with algorithms that recognize these types of waves and immediately sends warning data to a tsunami warning center, via the buoy, when it senses one of these waves. As a major support contractor to NOAA's National Data
Launch of the buoy.
Buoy Center, SAIC has gained experience building, deploying and maintaining the DART buoys. The SAIC STB team built on this background as well as decades of experience designing and deploying ocean sensors in support of other U.S. government agencies. With the operational success that DARThas demonstrated, SAIC elected to build and test the STB to the same standards. As a result SAIC recently applied for and received a license from NOAA to build DART systems. Besides the buoy, SAIC has developed an end-to-end tsunami warning system that builds upon the country's existing disaster warning infrastructure. The system includes components that receive, processes, and analyzes buoy, seismic and tide gauge data; predictive tools and the Consequence Assessment Tool Set to provide decision support; operation center design and implementation; and Tsunami Buoy Operations and Maintenance support. "Our first buoy was deployed Oct. 25, 2006, approximately 200 nautical miles west of San Diego in 3,800 meters of water," said Lawson. "Just two weeks later, it was put to the test during an actual tsunami event. On Nov. 15, 2006, an 8.3 magnitude earthquake rocked the Kuril Islands, located between Japan and the Kamchatka Peninsula of Russia. That quake generated a small tsunami." (See chart on page 27) Waves from the tsunami propagated approximately 4,000 nautical miles across the Pacific Ocean in about nine hours- a speed of about 445 nautical miles per hour -- when the SAIC buoy detected them. "The buoy detected and reported the first tsunami waves arriving in the area," said Lawson. "Throughout that event, the SAIC Tsunami Buoy showed excellent correlation with data collected by a NOAA DART located 28 nautical miles north of it. Subsequent analysis revealed that the STB matched DART operational capabilities and performed flawlessly." The buoy proved its capabilities again on Jan. 13, 2007, when an 8.1 magnitude earthquake occurred in the same region and the STB detected the seismic event. "The timing of these Kuril Island events has been pretty unbelievable," said Lawson. "Less than 90 days after deploying the STB we were able to evaluate an actual tsunamigenic event and a seismic event during our operational testing. Due to the infrequency of these types of events, it might otherwise have been years before another tsunami occurs in this area. After the tsunamigenic event, our team felt like they had hit a grand slam home run. We look forward to participating in building a world-wide tsunami warning network."
April 2007
28 MTR
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