FY 2001

Early detection and real-time reporting of deep-ocean tsunamis

Bernard, E.N., F.I. González, C. Meinig, and H.B. Milburn

In Proceedings of the International Tsunami Symposium 2001 (ITS 2001), NTHMP Review Session, R-6, Seattle, WA, 7–10 August 2001, (on CD-ROM), 97–108 (2001)

The National Oceanic and Atmospheric Administration's (NOAA) Deep-ocean Assessment and Reporting of Tsunamis (DART) Project is an effort of the U.S. National Tsunami Hazard Mitigation Program (NTHMP) to develop an early tsunami detection and real-time reporting capability. Although seismic networks and coastal tide gauges are indispensable for assessing the hazard during an actual event, an improvement in the speed and accuracy of real-time forecasts of tsunami inundation for specific sites requires direct tsunami measurement between the source and a threatened community. Currently, only a network of real-time reporting, deep-ocean bottom pressure (BPR) stations can provide this capability. Numerous NOAA deployments of ever-improving prototype systems have culminated in the current operating network of DART stations in the North Pacific. DART data can be viewed online at http://tsunami.pmel.noaa.gov/dartqc/WaveWatcher. Network coverage is presently limited to known tsunamigenic zones that threaten U.S. coastal communities. Because tsunamis can be highly directional, DART stations must be properly spaced to provide reliable estimates of the primary direction and magnitude of the energy propagation. A method for detector siting will be presented that considers various tradeoffs between early tsunami detection, adequate source zone coverage, and DART system survivability. A proposed network will be presented that is designed to provide adequate coverage of tsunamis originating in source regions that threaten U.S. coastal communities: the Alaska Aleutian Subduction Zone, the Cascadia Subduction Zone, and the South American Seismic Zone.