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Nat Hazards (2013) 69:11231130 DOI 10.1007/s11069-013-0697-8
SHORT COMMUNICATION
N. Nirupama
Received: 12 March 2013 / Accepted: 15 April 2013 / Published online: 26 April 2013 Springer Science+Business Media Dordrecht 2013
1 Introduction
Tsunamis and storm surges belong to the class of long gravity waves like ocean tides and they can cause substantial coastal inundation, leading to loss of life and extensive damage. Supercially, the coastal effects from tsunamis and storm surges are quite similar, but dynamically they are very different. Tsunamis propagate through the deep oceans and strike the coastlines, whereas storm surges are only coastal phenomena and do not exist over the deeper part of the oceans. Tsunamis can affect 1001,000 s of kilometers along the length of a coastline, whereas storm surges at most can affect few tens of kilometers along a coast. The effects of storm surges are to some degree hemisphere dependent in the sense that in the northern hemisphere, the peak surge occurs to the right side of the hurricane track and in the southern hemisphere on the left side. For tsunamis, there is no such hemispheric distinction, except the fact that most of the tsunami energy propagates in a direction perpendicular to the fault line causing the earthquake. The hurricanes that generate storm surges can be seen several days earlier, even though the prediction of the exact location of the landfall is quite difcult and is prone to errors. No tsunami prediction can be given until the under ocean earthquake actually happens, and in this sense, the warning time for tsunamis is substantially smaller than for storm surges. In the case of tsunamis, initial ocean withdrawal is sometimes observed while no such phenomenon has been reported in the literature for storm surges. Tsunamis and storm surges are different in the duration of the ocean water staying on the land during inundation. In Japan, in some instances, only few minutes of elapsed time is observed between the occurrence of the earthquake and the tsunami impact on the coastline. In such cases, no tsunami warning system would be very effective, and the earthquake itself has to be used as early warning. The energy contained in tsunami and storm surge wave systems differs substantially.
Tsunami waves, tides, and storm surges are long...