ALBERT

Description: Many beaches in Penang island were severely inundated by the 26 December 2004 Indian Ocean mega tsunami with 57 deaths recorded. It is anticipated that the next big tsunami will cause even more damages to beaches in Penang. Hence, developing community resilience against the risks of the next tsunami is essential. Resilience entails many interlinked components, beginning with a good understanding of the inundation scenarios critical to community evacuation and resilience preparation. Inundation scenarios are developed from tsunami simulations involving all three phases of tsunami generation, propagation and run-up. Accurate and high-resolution bathymetric–topographic maps are essential for simulations of tsunami wave inundation along beaches. Bathymetric maps contain information on the depths of landforms below sea level while topographic maps reveal the elevation of landforms above sea level. Bathymetric and topographic datasets for Malaysia are, however, currently not integrated and are available separately and in different formats, not suitable for inundation simulations. Bathymetric data are controlled by the National Hydrographic Centre (NHC) of the Royal Malaysian Navy while topographic data are serviced by the Department of Survey and Mapping Malaysia (JUPEM). It is highly desirable to have seamless integration of high-resolution bathymetric and topographic data for tsunami simulations and for other scientific studies. In this paper, we develop a robust method for integrating the NHC bathymetric and JUPEM topographic data into a regularly-spaced grid system essential for tsunami simulation. A primary objective of this paper is to develop the best Digital Elevation and Bathymetry Model (DEBM) for Penang based upon the most suitable and accurate interpolation method for integrating bathymetric and topographic data with minimal interpolation errors. We analyze four commonly used interpolation methods for generating gridded topographic and bathymetric surfaces, namely (i) Kriging, (ii) Multiquadric (MQ), (iii) Thin Plate Spline (TPS) and (iv) Inverse Distance to Power (IDP). The study illustrated that the Kriging interpolation method produces an integrated bathymetric and topographic surface that best approximates the admiralty nautical chart of Penang essential for tsunami run-up and inundation simulations. Tsunami inundation scenarios critical to risk analysis and mitigation could then be developed using this DEBM for various earthquake scenarios, as presented in this paper for the 2004 Indian Ocean Tsunami.

Description: The Andaman tsunami that occurred on 26 December 2004 has initiated and sustained keen research interest on modeling the characteristics and impacts of tsunami, with particular reference to tsunami wave heights, velocities and travel times. We have developed an in-house tsunami simulation model known as TUNA based upon the shallow water equations SWE for the purpose of simulating these tsunami characteristics. In this paper we present simulated tsunami scenarios along Malaysian coasts in the Straits of Malacca due to a potential earthquake originating in the Andaman Sea. Linear shallow water equations (LSWE) are used in the deep ocean, without the friction and advection terms to reduce computational time. On the other hand, in regions with shallow depth and over the beaches, non-linear shallow water equations (NSWE) and moving boundary are used in TUNA. Simulation results with TUNA indicate satisfactory performance when compared to simulation results from COMCOT and on-site survey results for the 2004 Andaman tsunami. Finally we discuss future enhancement of TUNA to improve its performance and to extend its applications to include ecological and water quality simulations.