IS TSUNAMI A THREAT TO JAMAICA?

One of the aims of Unit for Disaster Studies is to provide, as far as possible, accurate, up to date and state-of-the-art information on natural hazards to all concerned. Also, we hope that presentation of facts and data on the physical environment in which we live shall stimulate young minds who may wish to select environmental topics for their school project work. We see the news media as an effective medium for timely public education and also an essential component in all the efforts towards protection against natural disasters.

Our first concern is that in describing natural hazards and disasters we should speak the same language. It is not uncommon to find situations where different phrases to describe the same phenomenon by the scientific community and media create confusion in people's minds. Moreover, from a practical point of view, and as is the practice in the medical profession, for example, curing of a specific ailment and future protection from it depends on a correct diagnosis. The process of diagnosis in turn depends on an accurate description of the problem and its history by the patient, confirmation by laboratory tests where necessary, and investigators overall familiarity with the disease in question. Similarly, in order to practice prevention and loss reduction from natural hazards we must know exactly what it is that we wish to correct.

We recommend to Office of Disaster Preparedness and Emergency Management (ODPEM) that a working group be established, as a matter of priority, to standardize the definitions and usage of various natural hazard related terms following the relevant international conventions.
What is a tsunami and how does it originate?
_{[NOTE by the editor: in Japanese, the plural of 'tsunami' is 'tsunami', like in English 'sheep' is the plural of 'sheep'. However, common usage has validated retaining the anglized plural "tsunamis"]}

Tsunamis are not "tidal waves" for they have nothing to do with the tides - which are caused by gravitational forces of the moon and sun.
They are sea waves caused by various processes as explained below.
Storm surges are an abnormal rise in sea water level associated with hurricanes and other storms at sea. These processes result in the flooding of the coastline termed as "coastal flooding". The effects of coastal flooding caused by tsunamis are the same as those of storm surges. Flooding associated with the runoff in streams is "riverine flooding". In this article we are concerned with tsunamis only.
A gravity wave may propagate in seawater from a large disturbance of the sea floor started by an earthquake, eruption of a submarine volcano, or a massive landslide. Such a wave is called a tsunami, following a Japanese word meaning, " harbour waves". In the English-language tsunamis (soo-NAHM-ee) are termed seismic sea waves; in French, vagues sismique and raz de maree; and in Spanish, maremoto. Tsunamis are relatively more common in the area of the Pacific Ocean and especially along the Pacific Rim.