Introduction Tsunami; Japanese meaningharbor wave is a series of huge wavesgenerates due to mostly undersea earthquakes, undersea land slides, volcaniceruption and meteorite strike. Recently Sri Lanka was subjected to a tragicmega tsunami in 2004 due to an earthquake in Sumathra island magnitude of 9.0Richter scale losing 38000 lives and injuring 20000 people. Most earthquakesoccurred in the subduction zones are responsible for tsunamis. Sri Lanka isexposed to Tsunamis generated in two subduction zones, Sundra Trench located tothe east and Makran fault located to the northwest of the country. Severalalerts have been issued to Sri Lanka about Sundra trench generated tsunamiafter 2004.
Up to now though there are no alerts been issued about the Tsunamisgenerated in Makran fault, It is important to study Tsunami events generated inboth subduction zones and asses the exposure of Sri Lanka developing effectiveproper early warning system. Problem Statement Any natural disaster resultsa tragedy with its magnitude of impact. A natural hazard like Tsunami becomestragedy with its amount of damages to the people and properties mainly incoastal zone. Since this kind of disasters can not be avoided what can be doneis to control the amount of damages.
For that proper assessment of Tsunamiimpact and proper early warning system has to be established. Sri Lankareceives alerts about Tsunami events mainly from Indian Ocean Tsunami WarningSystem (IOTWS) through National Tsunami Warning Centre, Department of Meteorology.Since Sri Lanka does not own a proper database to predict exposing areas aftera Tsunami, it is important to develop such a database to reduce the damages tothe country.
Significance of the research After 2004 Tsunami event SriLanka got Tsunami warnings on 26 March 2005 with Richter scale 8.6, 12September 2007 with Richter scale 8.4 and 11 April 2011 with Richter scale 8.2.Thisimplies that Sri Lanka will have to face Tsunamis in future. Sri Lanka is exposed to severalTsunamis generated in Sundra trench and Makran fault. Those two subductionzones are 1000-2000 kilometers far away from Sri Lanka. So we have enough timeavailable for evacuation.
If Sri Lanka has a proper database for the evacuationit is easy for our National Tsunami Warning Centre to give warnings. Theresearch is conducted to prepare a database about exposure of Galle coast inTsunami events. And after evacuation accurate warnings should be given topublic. Otherwise damages can be occurred due to false warnings. Scope of the study The research mainly targets to develop a database todetermine the exposure of Southern coast of Sri Lanka in a Tsunami event.
Mainly Galle harbor area is concerned since that area was severely damaged bythe past 2004 Tsunami. Aims and objectives of the research The main objective is todevelop a database for the possible use in a Tsunami early warning system. Andwith that developed database it’s expected to determine the followingcharacteristics of tsunamis generated in Sundra trench and Makran fault inorder to assess the level of exposure of the Southern coast of the country.· Potential tsunami events that can be affected toSri Lankan Southern Coast· Tsunami inundation characteristics (extent,depth etc)· Tsunami arrival time and maximum wave height inshallow water