Insight into the 2004 Sumatra–Andaman earthquake from GPS measurements in southeast Asia

Abstract

Data collected at approximately 60 Global Positioning System (GPS) sites in southeast Asia show the crustal deformation caused by the 26 December 2004 Sumatra-Andaman earthquake at an unprecedented large scale. Small but significant co-seismic jumps are clearly detected more than 3,000 km from the earthquake epicentre. The nearest sites, still more than 400 km away, show displacements of 10 cm or more. Here we show that the rupture plane for this earthquake must have been at least 1,000 km long and that non-homogeneous slip is required to fit the large displacement gradients revealed by the GPS measurements. Our kinematic analysis of the GPS recordings indicates that the centroid of released deformation is located at least 200 km north of the seismological epicentre. It also provides evidence that the rupture propagated northward sufficiently fast for stations in northern Thailand to have reached their final positions less than 10 min after the earthquake, hence ruling out the hypothesis of a silent slow aseismic rupture.

Seismic nails in various geodynamic conditions

“…Смещение поверхности Зондской зоны субдукции, по данным GPS, во время Суматринского землетрясения 2004 г. [Vigny et al, 2005]. Чередование сильных цунамигенных и нецунамиген-ных землетрясений.…”

Co-seismic fault geometry and slip distribution of the 26 December 2004, giant Sumatra–Andaman earthquake constrained by GPS, coral reef, and remote sensing data

“…The first one is derived from GPS observations from a group of survey mode stations located in southeast Asia area, particularly in the Malaysian Peninsula (Vigny et al 2005). This data set provides crucial constraints to the intermediate field of co-seismic deformation for this earthquake.…”

“…Their study, however, was done using mainly far-field data and could not provide detailed solution for slip distribution. Another geodetic study by Vigny et al (2005) incorporated continuous GPS data from a network located in the Malai Peninsular, which strengthened observations in the intermediate field and enabled them to improve the spatial resolution of rupture distribution. Their result showed two peaks of slip along fault, spanning regions 48N-78N and 88N-128N, respectively.…”

“…More co-seismic deformation data were obtained by Subarya et al (2006), including GPS data acquired from the northern Sumatra island, sea floor vertical uplift/subsidence from coral reef measurements, and positions of pivot line from satellite image data around the Simeulue, Nicobar, and Andaman islands. Combined with GPS data of Vigny et al (2005), they attempted two models: one after Ammon et al's (2005) fault geometry and the other approximating a curved fault plane. Both of the models deduced seismic moment of 8.8 9 10 22 N m, corresponding to M W 9.22.…”

Airborne laser scanning : for forested landslides investigation in temperate and tropical invironments

“…The current tectonic situation is related to the subduction of the Australian plate under the Sunda plate (with movement of about 34 mm/year), producing large earthquakes along the Sumatran subduction zone and the Sumatran transform fault (Vigny et al, 2005;Yan et al, 2006). Also the divergent boundary effect of the Sagaing and Sumatra right-slip faults poses an explicit implication on the seismic situation in Malaysia.…”