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
Tsunami Detection Technology
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
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)
Deep-ocean Assessment and Reporting of Tsunamis
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
Acoustic Release
Anchor
Acoustic modem transducer
BPR
Battery case
Transducer
Tsunami ForecastingMeasurement Requirements
1. Measurement type - tsunami amplitude over time for input into forecast models
2. Measurement accuracy - 0.5 cm3. Measurement sample rate – 1 min or
less4. Measurement processing – within 2 min5. Measurement availability – within 5
minutes to assimilate into forecast models
Tsunami Forecasts
• 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
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)
Model coastal forecast
QuickTime™ and aCinepak decompressor
are needed to see this picture.
Hilo Harbor bathymetry