Uplift and subsidence associated with the great Aceh-Andaman earthquake of 2004

TitleUplift and subsidence associated with the great Aceh-Andaman earthquake of 2004
Publication TypeJournal Article
Year of Publication2006
AuthorsMeltzner AJ, Sieh KE, Abrams M, Agnew DC, Avouac J-P, Natawidjaja DH
JournalJournal of Geophysical Research-Solid Earth
Volume111
Date PublishedFeb
ISBN Number0148-0227
Accession NumberWOS:000239201600002
Abstract

Rupture of the Sunda megathrust on 26 December 2004 produced broad regions of uplift and subsidence. We define the pivot line separating these regions as a first step in defining the lateral extent and the downdip limit of rupture during that great M(w) approximate to 9.2 earthquake. In the region of the Andaman and Nicobar islands we rely exclusively on the interpretation of satellite imagery and a tidal model. At the southern limit of the great rupture we rely principally on field measurements of emerged coral microatolls. Uplift extends from the middle of Simeulue Island, Sumatra, at similar to 2.5 degrees N, to Preparis Island, Myanmar (Burma), at similar to 14.9 degrees N. Thus the rupture is similar to 1600 km long. The distance from the pivot line to the trench varies appreciably. The northern and western Andaman Islands rose, whereas the southern and eastern portion of the islands subsided. The Nicobar Islands and the west coast of Aceh province, Sumatra, subsided. Tilt at the southern end of the rupture is steep; the distance from 1.5 m of uplift to the pivot line is just 60 km. Our method of using satellite imagery to recognize changes in elevation relative to sea surface height and of using a tidal model to place quantitative bounds on coseismic uplift or subsidence is a novel approach that can be adapted to other forms of remote sensing and can be applied to other subduction zones in tropical regions.

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