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 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

One Hour Impact Zone

Tsunameter Deployment for 30, 60, 90 Minutes

Tsunami Forecasting Measurement Requirements 1. Measurement type - tsunami amplitude over time for input into forecast models 2. Measurement accuracy 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

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)

Approach and Example: Distant Tsunami Hilo, HI 17 November 2003

Model database Unit sources for pre-computed tsunami propagation scenarios

NOAA Tsunami Forecast M w =7.5 3cm -3 3cm -3 Seismic data DART data

NOAA Tsunami Forecast 3cm -3 3cm -3 Model offshore forecast

Model coastal forecast Hilo Harbor bathymetry

Tsunami Forecast at Hilo

Approach and Example: Local Tsunami Crescent City, CA 14 June 2005

14 June 2005 California Non-Destructive Tsunami

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