Assessment of potential tsunamigenic seismic hazard to Sri Lanka

Purpose: The purpose of this paper is to present an assessment of the potential tsunamigenic seismic hazard to Sri Lanka from all active subduction zones in the Indian Ocean Basin. Design/methodology/approach: The assessment was based on previous studies as well as past seismicity of the subducion zones concerned. Findings: Accordingly, four seismic zones capable of generating teletsunamis that could reach Sri Lanka have been identified, namely, Northern Andaman-Myanmar, Northern Sumatra-Andaman and Southern Sumatra in the Sunda trench and Makran in the Northern Arabian Sea. Moreover, plausible worst-case earthquake scenarios and respective fault parameters for each of these seismic zones have been recommended. Research limitations/implications: However, other potential tsunami sources such as seismic activity in the near-field, submarine landslides and volcanic eruptions have not been considered. Practical implications: Numerical simulations of tsunami propagation have been carried out for each of the four scenarios in order to assess the potential impact along the coastline of Sri Lanka. Such information relating to the spatial distribution of the likely tsunami amplitudes and arrival times for Sri Lanka would help authorities responsible for evacuation to make a better judgment as to the level of threat in different areas along the coastline, and act accordingly, if a large earthquake were to occur in any of the subduction zones in the Indian Ocean. Originality/value: In the absence of comprehensive probabilistic assessments of the tsunami hazard to Sri Lanka, this paper's recommendations would provide the necessary framework for the development of deterministic tsunami hazard maps for the shoreline of Sri Lanka.