These guidelines have been prepared as one of the activities of Working Group 3 (Risk Assessment) of the Intergovernmental Coordination Group (ICG) of the Indian Ocean Tsunami Warning and Mitigation System (IOTWS).
In this section, the Guidelines address the possibility and the probability of a tsunami impact on a country’s coast. As an introduction to the procedure for hazard assessment, the document describes the scientific background to tsunami occurrence in the Indian Ocean region, taking into account their sources and their geological causes, the ways in which tsunamis travel from those sources to shores near and far, and the challenge of preparing for catastrophic tsunamis that happen centuries apart.
This section explains how the scientific understanding of tsunamis in the region is being developed from research by the international scientific community. This account of the hazard context is followed by guidance on the procedures for countries to carry out their own hazard assessments in respect of tsunami impacts on their coasts.
The guidance takes into account the likelihood of occurrence and also the ways in which a tsunami may be modified (in terms of its height and momentum) by the specific coastal physiography. The assessment aims to delineate the parameters of potential inundation and inform local and/or national authorities on the likelihood of such impacts in relation to a timescale relevant to their coastal management and planning.