State of Tsunami Science and Early Warnings Dr. François Schindelé, CEA-DASE Chairman of the International Coordination Group for the Tsunami Warning System in the Pacific ICG/ITSU.
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State of Tsunami Science and Early Warnings Dr. François Schindelé, CEA-DASE Chairman of the International Coordination Group for the Tsunami Warning System in the Pacific ICG/ITSU State of Tsunami Science M 8.7 TSUNAMIS TSUNAMIS 1946 Tsunami Destruction in Hilo, Hawaii TSUNAMIS April 1, 1946 Tsunami at Hilo, Hawaii What is a Tsunami ? PERU TSUNAMI 23 JUN 2001 2033 UTC 16.2S 73.4W Mw=8.4 SERIES (4-5 large) of OCEAN WAVES MOST generated by EARTHQUAKES 4 to 60 MINUTES between WAVE CRESTS AMPLITUDE : A few cm to 20 m SPEED depends on WATER DEPTH : arround 800 km/h in deep ocean , 40 km/h close to the coast Arica, Chile Hazard Assessment COMPONENT TECHNOLOGY 1. ASSESSMENT • Historical Studies • Field Surveys • Numerical Simul PRODUCT • Historical Data Base • Inundation Maps Tsunami Observation Run-up Map - Aleutians 1946 Directivity Tsunami Generation Tsunami Generation Tsunami Generation Tsunami Generation Numerical Modeling Tsunami generated by Earthquake 1 Generation Parameters Initiation North Strike Dip Dislocation Slope Length Width Numerical Modeling 2 Propagation z =(x ,y) h= h(x,y) tsunami v=[u(x,y);v(x,y);0)] y Sea bottom x ( h ) .v (h ) 0 t v ( v.) v g f t Numerical Modeling 3 Numerical Mareograms - Inundation Each bay Données : Grids bathymetry and topography Numerical Modeling • Tsunami generated by landslide Generation Propagation Inundation 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Aftershocs Rupture zone Main shoc 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Initiation 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Maximum Tsunami height (in deep ocean) 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Maximum Tsunami height Directivity due to the focal mechanism 1m 0.1 m Amplitud very different at the same distance ratio >10 Less damage on the coast at > 500 km than in front at 4000 km 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Tsunami 2h 1h 1h 2h 3h Travel Time 26 December 2004 PTWC OPERATIONAL ACTIVITIES Tsunami Sri Lanka Colombo Sea-level data Arrival time : 2h40 after EQ Amplitude > 2m State of Early Warnings State of Early Warnings 1 Detection of Large Earthquakes (M > 7.0) Seismic Network 1 Real Time Data 2 Broad Band or long period seismometers 2 Tsunami Detection Sea level Network 1 Near Real Time Data 2 Tide gage, pressure gage, DART boye Hazard Reduction Strategy: Warning Guidance COMPONENT 3. WARNING GUIDANCE TECHNOLOGY • Measurement • Telecomm • Numerical Simul DART Rat Island, 17 Nov 2003 PRODUCT • Early Detection • Real-Time Data • Wave Forecast • Warning Dissem “to the last km” ACTIVITIES PTWC PTWC OPERATIONAL ACTIVITIES 1 RAPID INITIAL WARNING : COLLECTION of SEISMIC DATA (Real Time) ACTIVITIES PTWC PTWC OPERATIONAL ACTIVITIES 1 RAPID INITIAL WARNING : Automatic ANALYSIS of SEISMIC DATA Detection, location, magnitude estimation Manual verification (geophysicist) If Epicenter located under the ocean or on the coast The focal depth < 60 km And the Magnitude > 7.8 A tsunami can be generated EARLY WARNING TREMORS SYSTEM TREMORS Sismometers ACTIVITIES PTWC PTWC OPERATIONAL ACTIVITIES 2 CONFIRM AND MONITOR THE TSUNAMI : COLLECTION and ANALYSIS of WATER LEVEL DATA ACTIVITIES PTWC PTWC OPERATIONAL ACTIVITIES 2 CONFIRM AND MONITOR THE TSUNAMI : Tsunami warning is confirmed if the tsunami amplitude is greater than 50cm - 1 m in the gages Tsunami warning is canceled in the other cases PTWC OPERATIONAL ACTIVITIES Hazard Reduction Strategy: Assessment, Preparedness, Warning Hazard Assessment Indian Ocean IOTWS Sea Level Network Subduction zone 1 Indian Ocean Warning Center National Warning Centers