Risk Assessment of the Tsunami Hazard

Abstract

With the exception of the exceedingly rare impact of large meteorites, there are certainly no other natural hazards which are capable of ravaging such vast expanses of our planet with an intensity and suddenness comparable to that of large earthquakes. But even the effects of such large earthquakes are relatively localized compared to the devastating impact that their offsprings, tsunamis, can have, often across an entire ocean.

When the tsunami risk is potentially life-threatening or damaging to property, as often is the case, there is a paramount need to evaluate this risk in order to reduce or mitigate factors endangering public safety and property in coastal communities which have been historically impacted by such natural hazards. The risk potential of tsunamis is of extensive interest to governmental, non-governmental agencies, and to industries and the public in general. The interest of the insurance industry must also be directed toward this risk potential, particularly since in the last twenty years we have witnessed an unprecedented development of the coastal regions in most of the developed and developing countries of the world. Presently, the tsunami risk potential is frequently included in the coverage of insurance policies either explicitly or by implication.

Because the tsunami hazard frequency in the Pacific is the highest, most efforts in risk assessment and hazard management have concentrated in this area of the world. Other communities in other parts of the world are not immune to the tsunami hazard. No matter how remote, the likelihood of a tsunami should be considered in developing coastal zone management and land use. While some degree of risk is acceptable, government agencies should promote new development and population growth in areas of greater safety and less potential risk. These agencies have the responsibility of evaluating the tsunami hazard and establishing adequate warning procedures to protect the communities under their jurisdiction. Furthermore, these agencies should establish proper training for public safety personnel, and formulate land-use regulations for given coastal areas particularly if these areas are known to have sustained tsunami damage in the past. Finally, in designing important engineering structures in the coastal zone, the risk resulting from the tsunami hazard should be evaluated and construction should incorporate adequate safety features. This paper provides some of the appropriate guidelines and methodology needed for the evaluation of the tsunami risk in terms of frequency of occurrence, severity of impact, design adequacy of important coastal structures, and finally, in terms of preparedness and planning for hazard mitigation.