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Tsunami Warning System Elements IOC Assessment Mission to Indonesia 29 August-1 September 2005. Levels of Tsunami Warning Systems. Level I: Basic/Minimal Earthquake detection Warning/advisory dissemination system Educated public able to act appropriately Level II: Standard
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Tsunami Warning System ElementsIOC Assessment Mission to Indonesia29 August-1 September 2005
Levels of Tsunami Warning Systems • Level I: Basic/Minimal • Earthquake detection • Warning/advisory dissemination system • Educated public able to act appropriately • Level II: Standard • Earthquake detection • Tsunami detection • Warning/advisory dissemination system • Educated public able to act appropriately
Levels of Tsunami Warning Systems • Level III: Advanced • Earthquake detection • Tsunami detection • Tsunami forecast • Warning/advisory dissemination system • Educated public able to act appropriately
Earthquake Very advanced Global network of real-time digital broadband seismometers Earthquake location and magnitude in minutes for any location in the world Tsunami Relatively undeveloped A few tsunameters in Pacific Global network of real-time tide gauges with 2-15 minute sample rates But, often located in harbors and other protected areas that filter out tsunami signal Tsunami Detection Technology
Deep-ocean Assessment and Reporting of Tsunamis DART Technology development effort one of four key issues in the US National Tsunami Hazard Mitigation Program 1996 Implementation Plan: Quickly confirm potentially destructive tsunamis and reduce false alarms. (NTHMP Steering Group, 1996) DART I
DART II Concept • Bottom Pressure Recorder (BPR) measures small changes in pressure at the seafloor. Data sent acoustically to surface buoy, then via satellite (Iridium) to the Warning Centers. • Normal transmissions: Hourly reporting of 15 minute data to confirm system readiness. • Two Event Modes: • Automatic: Triggered by seismic or tsunami wave • Request: Warning Center triggers data stream
Pressure Transducer(heart of the system) • Manufactured by Paroscientific, Inc. in Redmond, Washington, USA • Operates in depths from 0 –6850 meters • Piezoelectric sensor yields high resolution with low noise. • DART system resolution is 0.2 cm of sea water
BPR Instrument and Platform Transducer AcousticRelease Acoustic modem transducer BPR Battery case Anchor
Tsunami ForecastingMeasurement Requirements 1. Measurement type - tsunami amplitude over time for input into forecast models 2. Measurement accuracy - 0.5 cm 3. Measurement sample rate– 1 min or less 4. Measurement processing– within 2 min 5. Measurement availability– within 5 minutes to assimilate into forecast models
Minutes to hours of warning time Real-time tsunameters and numerical models Pre-computed scenarios used to give first estimates, updated by real-time tsunameter data Real time tsunameter data reduce false alarms Deep ocean models link to near shore models to give inundation predictions Tsunami Forecasts
Operational Tsunami Forecasting • Detection: Tsunami detection networks in critical areas • Modeling: Vast ocean areas with no tsunami measurements requires modeling • Forecast: Effective operational forecasts must integrate real time measurement and modeling • Measurement: DART buoys • Forecast: Tsunami Forecast Model (Propagation and inundation)
Approach and Example: Distant TsunamiHilo, HI 17 November 2003
Model database Unit sources for pre-computed tsunami propagation scenarios
3cm -3 Mw=7.5 3cm -3 NOAA Tsunami Forecast DART data Seismic data
3cm -3 3cm -3 NOAA Tsunami Forecast Model offshore forecast
Model coastal forecast Hilo Harbor bathymetry
Approach and Example: Local Tsunami Crescent City, CA 14 June 2005
First estimate based on pre computed scenarios Revised model based on DART data
14 June 2005 California Earthquake: Tsunami Forecast using DART data
Indian Ocean Tsunami Warning System • Intergovernmental Oceanographic Commission • Perth ICG working groups on: • Seismic networks • Tide stations • DART Operators Group • Modeling • Hazard and Risk Analysis • Regional Center Interoperability • Context for multi-lateral cooperation and assistance