A satellite view of internal waves induced by the Indian Ocean tsunami

Abstract

At 08:45 local time (02:45 GMT) on 26 December 2004, 1 h and 45 min after the Sumatra Earthquakes of magnitude 9.3, a devastating tsunami struck the east coast of Sri Lanka. Nearly 2 h and 30 min after the wave hit the coast, a weather satellite passed over Sri Lanka's coastal zone providing a rare glimpse of internal waves along the continental slope due to this tsunami. The satellite imagery indicates wave‐like features from the tsunami being reflected, diffracted, and scattered off the steep continental slope and submarine canyons adjacent to Sri Lanka. The energetic wave and its modification to internal waves possibly eroded sediment from the sea floor and transported it to the sea surface. Solitary features generated by internal waves can explain the observed pattern. Future modelling approaches considering these nonlinear interactions would be required for a better understanding of the tsunami behaviour in the coastal zone, where its destructive effects are most prominent.

Acknowledgements

We thank Liam Gumley of the Space Science and Engineering Center, University of Wisconsin‐Madison for providing figure 1. We also thank Klaus Hasselmann, Jim Gower, Herrman‐Rudolf Kudraß, and Detlef Quadfasel for fruitful discussions improving the quality of the paper. A special acknowledgement goes to the reviewers of this paper, Dr Hui Fan and an anonymous reviewer, whose suggestions and comments were invaluable in improving the paper. Arne Winguth was supported by NASA grant NAG5‐11245.