The 2004 Indian Ocean tsunami: Tsunami source model from satellite altimetry

Abstract

Satellite altimetry measurements of sea surface heights for the first-time captured the Indian Ocean tsunami generated from the December 2004 great Sumatra earthquake. Analysis of the sea surface height profile suggests that the tsunami source, or the seafloor deformation, of the great earthquake propagated to the north at an extremely slow speed of less than 1 km/sec on average for the entire 1300-km-long segment along the northern Sumatra-Nicobar-Andaman Trench. The extremely slow propagation speed produces a very long duration of tens minutes, longer than earthquake source duration estimated (480-500 sec) from short-period P-wave radiation. The satellite altimetry data requires a total seismic moment of 9.86 × 10 22 Nm (Mw=9.3). This estimate is approximately 2.5 times larger than the value from long-period surface wave analysis but nearly the same as that from the ultra-long-period normal mode study. The maximum amount of slip (∼30 m) is identified in an offshore region closest to the northern most part of Sumatra where the largest tsunami run-up heights were observed.

On the solitary wave paradigm for tsunamis

“…[83] Typical historic fault areas of major earthquakes are listed in, e.g., Geist [1999], and details on the recent Sumatra earthquake can be found in, e.g., Stein and Okal [2005], Hirata et al [2006], Fujii and Satake [2007] and Geist et al [2007].…”

Can undersea voltage measurements detect tsunamis?

“…The time step for the computation was chosen as 10 seconds to satisfy a stability condition. We use the tsunami source region and the vertical sea surface displacement estimated by Hirata et al (2006) as the initial condition for the model. The model output (vertically integrated transport) is generated for every 1…”

Operational tsunami modelling with TsunAWI – recent developments and applications

“…Also in this respect, the modified orientation improves the results considerably. In fact, the unsatisfactory inundation result obtained with the original source was the reason to test the strike angles proposed by Hirata et al (2006) for the southern subfaults, because they have the largest impact on the inundation in Banda Aceh.…”

“…The strike angle of subfaults A/C is changed from 340/340 • as proposed by Tanioka et al (2006) to 290/320 • . This change is motivated by Hirata et al (2006), who optimised source parameters with respect to satellite altimetry. The geometry differs from Tanioka's source.…”