Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia

We utilize coral microatolls in western Sumatra to document vertical deformation associated with subduction. Microatolls are very sensitive to fluctuations in sea level and thus act as natural tide gauges. They record not only the magnitude of vertical deformation associated with earthquakes (paleos...

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Main Authors: Natawidjaja, Danny H., Ward, Steven N., Suwargadi, Bambang W., Sieh, Kerry, Cheng, Hai, Edwards, R. Lawrence, Galetzka, John
Format: Article
Language:English
Published: 2012
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Online Access:https://hdl.handle.net/10356/95667
http://hdl.handle.net/10220/8477
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-956672020-09-26T21:32:27Z Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia Natawidjaja, Danny H. Ward, Steven N. Suwargadi, Bambang W. Sieh, Kerry Cheng, Hai Edwards, R. Lawrence Galetzka, John DRNTU::Science::Geology::Volcanoes and earthquakes We utilize coral microatolls in western Sumatra to document vertical deformation associated with subduction. Microatolls are very sensitive to fluctuations in sea level and thus act as natural tide gauges. They record not only the magnitude of vertical deformation associated with earthquakes (paleoseismic data), but also continuously track the long-term aseismic deformation that occurs during the intervals between earthquakes (paleogeodetic data). This paper focuses on the twentieth century paleogeodetic history of the equatorial region. Our coral paleogeodetic record of the 1935 event reveals a classical example of deformations produced by seismic rupture of a shallow subduction interface. The site closest to the trench rose 90 cm, whereas sites further east sank by as much as 35 cm. Our model reproduces these paleogeodetic data with a 2.3 m slip event on the interface 88 to 125 km from the trench axis. Our coral paleogeodetic data reveal slow submergence during the decades before and after the event in the areas of coseismic emergence. Likewise, interseismic emergence occurred before and after the 1935 event in areas of coseismic submergence. Among the interesting phenomenon we have discovered in the coral record is evidence of a large aseismic slip or “silent event” in 1962, 27 years after the 1935 event. Paleogeodetic deformation rates in the decades before, after, and between the 1935 and 1962 events have varied both temporally and spatially. During the 25 years following the 1935 event, submergence rates were dramatically greater than in prior decades. During the past four decades, however, rates have been lower than in the preceding decades, but are still higher than they were prior to 1935. These paleogeodetic records enable us to model the kinematics of the subduction interface throughout the twentieth century. Published version 2012-09-06T04:28:39Z 2019-12-06T19:19:26Z 2012-09-06T04:28:39Z 2019-12-06T19:19:26Z 2004 2004 Journal Article Natawidjaja, D. H., Sieh, K., Ward, S. N., Cheng, H., Edwards, R. L., Galetzka, J., & Suwargadi, B. W. (2004). Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia. Journal of Geophysical Research, 109. 0148–0227 https://hdl.handle.net/10356/95667 http://hdl.handle.net/10220/8477 10.1029/2003JB002398 en Journal of geophysical research © 2004 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/10.1029/2003JB002398. 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. 34 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic DRNTU::Science::Geology::Volcanoes and earthquakes
spellingShingle DRNTU::Science::Geology::Volcanoes and earthquakes
Natawidjaja, Danny H.
Ward, Steven N.
Suwargadi, Bambang W.
Sieh, Kerry
Cheng, Hai
Edwards, R. Lawrence
Galetzka, John
Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
description We utilize coral microatolls in western Sumatra to document vertical deformation associated with subduction. Microatolls are very sensitive to fluctuations in sea level and thus act as natural tide gauges. They record not only the magnitude of vertical deformation associated with earthquakes (paleoseismic data), but also continuously track the long-term aseismic deformation that occurs during the intervals between earthquakes (paleogeodetic data). This paper focuses on the twentieth century paleogeodetic history of the equatorial region. Our coral paleogeodetic record of the 1935 event reveals a classical example of deformations produced by seismic rupture of a shallow subduction interface. The site closest to the trench rose 90 cm, whereas sites further east sank by as much as 35 cm. Our model reproduces these paleogeodetic data with a 2.3 m slip event on the interface 88 to 125 km from the trench axis. Our coral paleogeodetic data reveal slow submergence during the decades before and after the event in the areas of coseismic emergence. Likewise, interseismic emergence occurred before and after the 1935 event in areas of coseismic submergence. Among the interesting phenomenon we have discovered in the coral record is evidence of a large aseismic slip or “silent event” in 1962, 27 years after the 1935 event. Paleogeodetic deformation rates in the decades before, after, and between the 1935 and 1962 events have varied both temporally and spatially. During the 25 years following the 1935 event, submergence rates were dramatically greater than in prior decades. During the past four decades, however, rates have been lower than in the preceding decades, but are still higher than they were prior to 1935. These paleogeodetic records enable us to model the kinematics of the subduction interface throughout the twentieth century.
format Article
author Natawidjaja, Danny H.
Ward, Steven N.
Suwargadi, Bambang W.
Sieh, Kerry
Cheng, Hai
Edwards, R. Lawrence
Galetzka, John
author_facet Natawidjaja, Danny H.
Ward, Steven N.
Suwargadi, Bambang W.
Sieh, Kerry
Cheng, Hai
Edwards, R. Lawrence
Galetzka, John
author_sort Natawidjaja, Danny H.
title Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
title_short Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
title_full Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
title_fullStr Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
title_full_unstemmed Paleogeodetic records of seismic and aseismic subduction from central Sumatran microatolls, Indonesia
title_sort paleogeodetic records of seismic and aseismic subduction from central sumatran microatolls, indonesia
publishDate 2012
url https://hdl.handle.net/10356/95667
http://hdl.handle.net/10220/8477
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