Simulated Strong Ground Motions for the GreatM9.3 Sumatra–Andaman Earthquake of 26 December 2004

Abstract

On 26 December 2004, a devastating earthquake of M 9.3 occurred offshore northern Sumatra. Due to the size of this earthquake and the accompanying tsunami wave, disastrous consequences have been observed in several countries around the Indian Ocean. The tectonics in the region are characterized by the oblique, north-northeast-oriented subduction of the Indian–Australian plate under the Sunda microplate with a rate of 6–6.5 cm/yr. This oblique convergence results in strain partitioning, where the trench-perpendicular thrust faulting along the subducting slab accommodates the east–west component of the motion, whereas the north–south component of the motion is probably accommodated by the right-lateral strike-slip faulting along the Great Sumatran fault and the Mentawi fault. Source parameters of the 26 December 2004 event have been used for modeling the resulting ground motions in the nearby affected regions. Results give an insight on the importance of ground shaking in the total destruction of places like Banda Aceh, northern Sumatra, Indonesia. The modeling is performed for a multiasperity finite fault using a hybrid procedure combining deterministic modeling at low frequencies and semistochastic modeling at high frequencies. Results show that strong shaking was distributed over a large area including northwestern Sumatra and its offshore islands. In Banda Aceh, which experienced significant damage, bedrock velocities reached 60 cm/sec with duration of the shaking of ca. 150 sec. The largest ground motions occurred near the strongest asperities of the fault plane, where velocities of 200 cm/sec are modeled for bedrock conditions.

Sensitivity of Ground-Motion Simulations to Earthquake Source Parameters: A Case Study for Istanbul, Turkey

“…Point sources are summed using the empirical Green's function method of Irikura (1986). The methodology has been validated through comparison to recorded data in previous studies by and Sørensen et al (2007).…”

Reconnaissance report and preliminary ground motion simulation of the 12 May 2008 Wenchuan earthquake

“…Realistic estimates of the seismic hazard due to such events can be based on finite fault rupture scenarios. In this regard ground motions simulation methodologies, such as the one applied in this preliminary study and tested elsewhere (Bjerrum et al 2010;Sørensen et al 2007), can provide significant insight to the ground motion distribution and its complexity prior to such disastrous events, and can efficiently be used in earthquake preparedness programs.…”

“…This method has previously been validated in forensic e.g. for the 2000 Tottori (Japan) and 2004 Sumatra (Indonesia) earthquakes Sørensen et al 2007). The simulation is separated into two frequency ranges; low frequencies (0.1-1.0 Hz) and high frequencies (1.0-10 Hz).…”

Apparent stress scaling for tectonic and induced seismicity: Model and observations

“…For comparison, 4 tsunami earthquakes are considered: Peru, 1996, Nicaragua, 1992, Java 1994(Ihmlé, 1996Ihmlé et al, 1998;Bilek et al, 2004) and the Sumatra-Andaman 2004 destructive event (Choy and Boatwright, 2007;Sørensen et al, 2007;Banerjee et al, 2007).…”