Uplift and subsidence associated with the great Aceh-Andaman earthquake of 2004
Meltzner, Aron J.
Agnew, Duncan Carr
Hudnut, Kenneth W.
Natawidjaja, Danny H.
Date of Issue2006
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 Mw ≈ 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 ∼2.5°N, to Preparis Island, Myanmar (Burma), at ∼14.9°N. Thus the rupture is ∼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.
DRNTU::Science::Geology::Volcanoes and earthquakes
Journal of geophysical research
© 2006 AGU. This paper was published in Journal of Geophysical Research and is made available as an electronic reprint (preprint) with permission of American Geophysical Union. The paper can be found at: http://dx.doi.org/10.1029/2005JB003891. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.