TSUNAMIS ON THE COAST LINES OF INDIA Edit
- T. S. Murty
- A. Bapat
This article was published originally in : Science of Tsunami Hazards, Vol 17, No.3 (1999), p-167 to 172
Although the majority of the reported tsunamis are from littoral countries of the Pacific Ocean, there are a few cases of tsunamis in the Indian Ocean. The approximate length of the Indian coast is about 6000 kilometers. The coasts run from north to south and have two arms in the east and west with a tapering end at Kanyakumari.
The tsunamigenic earthquakes occur mostly at the following three locations; (1) The Andaman sea, (2) Area about 400-500 kilometers SSW of Sri Lanka (Ceylon), (3) The Arabian Sea about 70-100 kilometers south of Pakistan Coast -- off Karachi and Baluchistan.
The oldest record of tsunami is available from November 326 BC earthquake near the Indus delta/Kutch region. Alexander the Great was returning to Greece after his conquest and wanted to go back by a sea route. But an earthquake of large magnitude destroyed the mighty Macedonian fleet as reported by Lietzin (1974).
The earliest record of tsunami is reported to be about 1.5 meters at Chennai (formerly Madras) which was created due to the August 8, 1883 Krakatoa volcanic explosion in Indonesia.
An earthquake of magnitude 8.25 occurred about 70 kilometers south of Karachi (Pakistan) at 24.5 N and 63.0 E on November 27, 1945. This created a large tsunami of about 11.0 to 11.5 meters high on the coasts of India in the Kachchh region, as reported by Pendse (1945). An earthquake of magnitude 8.1 occurred in the Andaman Sea at 12.9 N and 92.5 E on June 26, 1941 and a tsunami hit the east coast of India. As per non-scientific/journalistic sources, the height of the tsunami was of the order of 0.75 to 1.25 meters. At the time no tide gauge was in operation. Mathematical calculations suggest that the height could be of the order of 1.0 meter.
There are a few more cases of earthquakes of magnitude less than 8.0 which have given rise to some smaller tsunamis.
- Bapat A., S.K.Guha and R.C.Kulkarni (1983). Catalogue of the earthquakes in India and neighbourhoods from the earliest period to 1979, published by the Indian Society for Earthquake Tech, Roorkee, India.
- Henry, R.F., and T.S.Murty (1995). Tsunami Amplification due to Resonance in Alberni Inlet : Normal Modes. Tsunami : Progress Publication, Disaster Prevention and Warning, 117-128. Edited by Y.Tsuchiya and N.Shuto, Kluwer publishers, Dordrecht, Netherlands.
- Lisitzin, E. (1974) Sea Level Changes, Elsevier Oceanographic Series, No.8, New York, 273 pages.
- Otto, P. and T.S.Murty (1996). Tsunami Travel Time Charts for the Indian Ocean, Report, National Tidal Facility, Flinders University of South Australia, Adelaide, 184 pages.
- Pendse, C.G. (1945). The Mekran Earthquake of the 28th November 1945, India Meteorological Department Scientific Notes, Vol.10, 141-145.