Early Warning System development for Tsunami and Storm surges in Indian Ocean. V. Ram Mohan R.R. Krishnamurthy

Transcription

1 Early Warning System development for Tsunami and Storm surges in Indian Ocean V. Ram Mohan R.R. Krishnamurthy School of Earth and Atmospheric Sciences University of Madras Chennai Training for Trainers September, 2007

2 History of Tsunami Events Total No of tsunami in the last 2 decades: 157 Tsunami with fatalities: 16 Teletsunami: 3

3 Fatalities from tsunami Date May 26, 1983 Aug.10, 88 Sept. 2, 92 Dec. 12, 92 July Feb. 15, 94 Jun. 2, 94 Nov. 4, 94 Location Japan & South Korea Solomon Islands Nicaragua Indonesia Sea of Japan Sumatra South of Java Skagway Fatalities ,

4 Fatalities from tsunami (Cont..) Date Nov. 14, 94 Jan. 1, 96 Feb. 17, 96 Feb. 21, 96 Jul. 17, 98 Aug. 17, 99 Nov. 26, 99 Jun. 23, 01 Total Location Mindanao Is. Philippines Sulawesi, Indonesia Irian Jaya, Indonesia North coast of Peru NW coast of Papua NG Izmit Bay, Turkey Vanuatu South Peru Fatalities

5 Fatality in Asian tsunami 228,000 as on

6 World s largest Tsunamigenic earthquakes Location Date UTC Magnitude Coordinates & Fatality Latitude Longitude Chile Fatality ~ S 73.05W Prince William Sound, Alaska ~ N W Off west coast of Northern Sumatra* 228, (3) 3.30N South Asian tsunami: Source USGS (2005), National Earthquakes Information Centre 95.78E

7 Causes The tsunami originated consequent to a massive earthquake with magnitude of 9.0 (9.3) on Richter scale at 00.58:53 hrs off Northern Sumatra coast More than one hundred aftershocks: none fortunately created tsunami

8 Time of Arrival of Tsunami in IST Andaman & Nicobar Chennai Port Paradip Port Visakhapatnam & Velankanni Tuticorin Neendakara (Kollam) Cochin Port Kanyakumari Marmagoa Kayankulam 7:25 hrs 8:50 hrs 9:00 hrs 9:05 hrs 9:51 hrs 10:45 hrs 11:10 hrs 11:45 hrs 12:20 hrs 12:30 hrs 0:43 hrs 2:22 hrs 2:32 hrs 2:37 hrs 3:23 hrs 4:17 hrs 4:42 hrs 5:17 hrs 5:52 hrs 6:02 hrs

9 Sketch Map of Tamil Nadu showing inundation in different locations Madras Adyar 0500 Porto Novo Kovalam Coleron R. Mahabalipuram Kalpakkam Kadalur Cheyyur Chunnampettai Marakkanam Pumbuhar Tarangambadi Karaikal Nagore Nagapattinam Velankanni Pondichery Cuddalore Vedaranyam Point Calimer Inundation in metres m Inundation in metres m

10 What is to be done? 1. Establishment of Early Warning System. 2. Modelling the propagation of the tsunami waves for Asian Tsunami 3. Validate inundation with Run the Model for different sources and earthquake parameters 5. Identify and warn the community in the vulnerable zones

11 Early Warning System for Tsunami 12 Bottom Pressure Recorders 10 in Bay of Bengal 2 in Arabian Sea 17 Tide Gauges NIOT Seismic data from IMD, Japan Meteorological Agency, Pacific Tsunami Warning Centre, etc INCOIS

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13 Locations of Tsunami Buoy System

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15 Role of INCIOS The earthquake information and data from BPR and Tide Gauges is being received in real time at INCOIS. One Bottom Pressure Recorder deployed in the deep ocean near Andaman Nicobar Island and is sending data and another is being installed. These recorders are key sensors whether a tsunami has been generated or not, and further confirmation is done by the Tide Gauges, located at coasts.

16 Early Warning Once the formation of tsunami and its propagation to Indian coast is conformed by BPR data based in the earthquake parameters and source, warnings are issued by INCOIS.

17 Tsunami Warning Schedule Alert - The occurrence of earthquake in a location in Indian Ocean with magnitude that can cause a tsunami The possibility of generation of tsunami will be confirmed only after information from the bottom sensors of EWS for T&S. Tsunami Hazard Zones: RED ALERT Zone 1: The tsunami can hit the coast within one hour. The community have less than an hour to evacuate and hence, are at greater risk.

18 Precautions for Zone 1 They should look for confirmation of the alert and prepare in advance for evacuation. It is possible that the communities in Zone 1 have already felt the earthquake and they have adopted the earthquake preparedness schedule. If they are in tsunami vulnerable regions, they should not wait for warning from INCOIS. Others can look for confirmation of tsunami alert.

19 Zone 2 Regions where tsunami is possible after 1 hours ORANGE ALERT Stakeholders can assemble, discuss and propagate the alert message in areas in Zone 2 as they have sufficient time to organize evacuation strategies and wait for the confirmation of alert that will be issued through media, public address system or any other communication dissemination process.

20 Alert Confirmed The generation of tsunami is confirmed by data from EWS for Tsunami. Activity for Zone 1 - Evacuate and go to safe zones. The tsunami shelters in such regions should be within the reach of the community. Activity for Zone 2 - Prepare for evacuation and go to safe zones.

21 Vulnerable zones It is envisaged to provide the details of possible run-up and inundation details of tsunami for different areas along with warning to facilitate evacuation to safe zones Alert withdrawn -The alert issued can be withdrawn at any stage.

22 Purpose of Modelling To understand the generation and propagation characteristics of tsunami To evaluate the coastal amplifications To estimate the potential effects on the coastal areas

23 Some Models available MOST (Methods Of Splitting Tsunami), developed at the University of Southern California (Titov and Synolakis, 1998) COMCOT (Cornell multi-grid coupled tsunami model), developed at Cornell University (Liu et al., 1994) TUNAMIN2, developed at Tokyo University in Japan (Imamura, 1996)

24 Tsunami Modelling by Kowalik 200 million grid points. It encompassed the entire world and it was performed on a CRAY X1 Supercomputer with 60 processors working parallelly in 60 subdomains. The running time of the model is reduced from 50 hours to 9 hrs by the parallelisation.

25 Result

26 Distribution of the tsunami amplitude in the Indian Ocean at hour 4 from the tsunami origin (after Kowalik)

27 Assumptions of a realistic model Correlation of the initial water displacements to tsunami wave length and period in the source region The model can be used for any generating mechanism - an earthquake, a landslide, or an impact event such as a rock fall or an asteroid.

28 Model used in the present study Widely used model, TSUNAMI N2 (which solves the non-linear form of the long wave equations), which is a modified form of TUNAMI N2 developed by Prof. Shuto and Prof. Imamura

29 Data input (Cont..) Earthquake Parameters Source, Earthquake magnitude, slip magnitude, fault length, fault width, strike, dip, rake and depth Bathymetry GEBCO, CMAP, NHO Charts, Echosounding records

30 Data input Onshore elevation SRTM GEBCO Survey by RTK, Total Station ALTM Toposheet

31 Software Requirement ArcGIS Mapping, Digitization, Merging data ERDAS Image rectification SURFER Gridding MatLab Changing the Surfer Grid to MatLab grid to run the Tsunami N2 model in FORTRAN and creation of animation Mike21 To extract CMAP data

32 Grids Grids A B C D Spacing Resolution 2502 m 834 m 278 m 92 m

33 Tsunami Modelling for East Coast Date, Sources considered and Magnitude 26 th December Sumatra 9.3 Mw 26 th June, North Andaman 7.7 Mw 31 st December, Carnicobar 7.9 Mw

34 Location of epicentre, aftershocks & extent of main fault rupture of Asian Tsunami with epicentre of 28 th March, 2005 tsunami source Location of source of tsunami in Indian Ocean Since

35 Conversion to MatLab Grid The Surfer grid is input in MatLab and MatLab grid is created Earthquake parameters is input in Fortran Programme to create a MatLab grid which shows the initial displacement in Tsunami generated location

36 Tsunami Modelling

37 Using Tsunami N2 Programme The final output of wave heights will be stored as MatLab grid The MatLab grid is used as GIS input runup and inundation is estimated

38 Result of Model for Marakkanam with Sumatra Source and 2004 Earthquake parameters Wave height in m

39 80 11'0"E 80 12'0"E 80 13'0"E Landuse/ Land Cover Map of 12 39'0"N 12 38'0"N Mamallapuram showing 12 37'0"N inundation Map 6:Composite Map showing the extent of Inundation in Mamallapuram village,tirukalukundram Tamil Nadu in relation to its Landuse. Legend. 200 m CRZ 500 m CRZ Ecr Inundatedarea Archaeological site Casuarina Cultivation Lagoon Mudflat Pond Prawn farm Resorts Saltpan Sand dune Sandybeach Scattered coconut Settlement and vegetation Shrubs Vegetation 12 39'0"N 12 38'0"N 12 37'0"N 12 36'0"N 80 11'0"E 80 12'0"E Scale ,000 Meters Prepared for DST Project "Mapping areas of Inundation Marakkanam to Kovalam" by Dr. V. Ram Mohan (Principal Investigator) Department of Geology, University of Madras Guindy campus, Chennai '0"E 12 36'0"N

40 Tsunami Model for Mumbai Location of 1945 Makran earthquake source Location Magnitude Depth Fault Length Fault Width Strike Dip Slip Magnitude Rake Angle 63 E, 24.5 N 8 Mw 30 km 200 km 100 km 270 deg 15 deg 15 m 90 deg

41 Inundation model for Mumbai During LWL Condition Inundation Line Shore Line No Inundation

42 Inundation model for Mumbai During MSL Condition Inundation Line Shore Line Inundation From the Model Versova and Juhu Ranges 70 to 300 m

43 Inundation model for Mumbai During HWL Condition Inundation polygon Shore Line Inundation From the Model Versova and Juhu Ranges 70 to 2100 m

44 Model Limitations (Cont..) Numerical models have certain error level depending on scheme and mesh size etc. Increasing mesh size for more accurate wave amplitudes and wave forms leads to longer computer processing time.

45 Model Limitations The earthquake parameters are based on information released by USGS however, the actual elevation of the sea floor cannot be determined until the data is collected in the field. Accurate estimate of seismic data is available well after the tsunami strikes Reflections due to barriers like island chains, etc towards the source and interaction can be determined precisely only if the accurate bathymetric data is known for these features.

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