Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra
The geomorphology and internal stratigraphy of modern coral microatolls show that all the outer arc Mentawai islands of West Sumatra have been subsiding over the past several decades. These same islands rose as much as 3 m during the giant megathrust earthquakes of 1797 and 1833, and the current sub...
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sg-ntu-dr.10356-955622020-09-26T21:35:31Z Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra Natawidjaja, Danny H. Suwargadi, Bambang W. Sieh, Kerry Galetzka, John Cheng, Hai Edwards, R. Lawrence Chlieh, Mohamed DRNTU::Science::Geology::Volcanoes and earthquakes The geomorphology and internal stratigraphy of modern coral microatolls show that all the outer arc Mentawai islands of West Sumatra have been subsiding over the past several decades. These same islands rose as much as 3 m during the giant megathrust earthquakes of 1797 and 1833, and the current subsidence probably reflects strain accumulation that will lead to future large earthquakes. Average subsidence rates over the past half century vary from 2 to 14 mm yr−1 and increase southwestward, toward the subduction trench. The pattern is consistent with rates of subsidence measured by a sparse network of continuously recording Global Positioning System (cGPS) stations and with locking of a 400-km-long section of the underlying subduction megathrust, between about 1°S and 4°S. This record of subsidence and tilting, extending nearly a century into the past, implies that the region is advancing toward the occurrence of another giant earthquake. However, evidence of episodic rather than steady subsidence reflects a behavior that is more complex than simple elastic strain accumulation and relief. Most prominent of these episodes is an extensive emergence/subsidence couplet in about 1962, which may be the result of rapid, aseismic slip on the megathrust, between the islands and the trench. Lower subsidence rates recorded by the corals since about 1985 may reflect failure on many small patches within the locked section of the megathrust. Published version 2012-09-06T01:49:46Z 2019-12-06T19:17:22Z 2012-09-06T01:49:46Z 2019-12-06T19:17:22Z 2007 2007 Journal Article Natawidjaja, D. H., Sieh, K., Galetzka, J., Suwargadi, B. W., Cheng, H., Edwards, R. L., & Chlieh, M. (2007). Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra. Journal of Geophysical Research, 112. 0148–0227 https://hdl.handle.net/10356/95562 http://hdl.handle.net/10220/8473 10.1029/2006JB004450 en Journal of geophysical research © 2007 American Geophysical Union. 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 the following official URL: http://dx.doi.org/10.1029/2006JB004450. 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. 27 p. application/pdf |
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DRNTU::Science::Geology::Volcanoes and earthquakes Natawidjaja, Danny H. Suwargadi, Bambang W. Sieh, Kerry Galetzka, John Cheng, Hai Edwards, R. Lawrence Chlieh, Mohamed Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
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The geomorphology and internal stratigraphy of modern coral microatolls show that all the outer arc Mentawai islands of West Sumatra have been subsiding over the past several decades. These same islands rose as much as 3 m during the giant megathrust earthquakes of 1797 and 1833, and the current subsidence probably reflects strain accumulation that will lead to future large earthquakes. Average subsidence rates over the past half century vary from 2 to 14 mm yr−1 and increase southwestward, toward the subduction trench. The pattern is consistent with rates of subsidence measured by a sparse network of continuously recording Global Positioning System (cGPS) stations and with locking of a 400-km-long section of the underlying subduction megathrust, between about 1°S and 4°S. This record of subsidence and tilting, extending nearly a century into the past, implies that the region is advancing toward the occurrence of another giant earthquake. However, evidence of episodic rather than steady subsidence reflects a behavior that is more complex than simple elastic strain accumulation and relief. Most prominent of these episodes is an extensive emergence/subsidence couplet in about 1962, which may be the result of rapid, aseismic slip on the megathrust, between the islands and the trench. Lower subsidence rates recorded by the corals since about 1985 may reflect failure on many small patches within the locked section of the megathrust. |
format |
Article |
author |
Natawidjaja, Danny H. Suwargadi, Bambang W. Sieh, Kerry Galetzka, John Cheng, Hai Edwards, R. Lawrence Chlieh, Mohamed |
author_facet |
Natawidjaja, Danny H. Suwargadi, Bambang W. Sieh, Kerry Galetzka, John Cheng, Hai Edwards, R. Lawrence Chlieh, Mohamed |
author_sort |
Natawidjaja, Danny H. |
title |
Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
title_short |
Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
title_full |
Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
title_fullStr |
Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
title_full_unstemmed |
Interseismic deformation above the Sunda megathrust recorded in coral microatolls of the Mentawai islands, West Sumatra |
title_sort |
interseismic deformation above the sunda megathrust recorded in coral microatolls of the mentawai islands, west sumatra |
publishDate |
2012 |
url |
https://hdl.handle.net/10356/95562 http://hdl.handle.net/10220/8473 |
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1681058991565701120 |