The 26 December 2004 Sumatra Earthquake and Tsunami Seen by Satellite Altimeters and GPS

Abstract

On 26 December 2004 a strong earthquake with an epicenter west of the coast of Sumatra generated a tsunami in the Indian Ocean. The earthquake had a magnitude of 9, which makes it a rare event since earthquakes greater than magnitude 8.5 have occured about once every 10 years since 1900 according to [5]. The last time a tsunami was generated by a magnitude 9 earthquake was on Good Friday 1964 off the coast of Alaska. The Sumatra earthquake and the tsunami that followed caused many victims in the countries surrounding the Indian Ocean. At the time of writing the death toll stands at 225000, which is an incredible number that is changing by the day. This article discusses two unique scientific aspects related to the earthquake and the tsunami. Four satellite altimeters picked up the traveling wave in the Indian Ocean, evidenced by the fact that a tsunami model matches the satellite observations. Early GPS observed displacements at a few sites in the Sumatra, Thailand, Malaysia region confirm the predictions of a geophysical model.