Three-dimensional seismic velocity structure in the Sichuan basin, China

We present a new three‐dimensional velocity model of the crust in the eastern margin of the Tibetan Plateau. The model describes the velocity structure of the Sichuan basin and surrounding thrust belts. The model consists of 3‐D surfaces representing major geologic unit contacts and faults and is pa...

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Main Authors: Wang, Maomao, Hubbard, Judith, Plesch, Andreas, Shaw, John H., Wang, Lining
Other Authors: Asian School of the Environment
Format: Article
Language:English
Published: 2018
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Online Access:https://hdl.handle.net/10356/88913
http://hdl.handle.net/10220/46982
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-889132020-09-26T21:27:18Z Three-dimensional seismic velocity structure in the Sichuan basin, China Wang, Maomao Hubbard, Judith Plesch, Andreas Shaw, John H. Wang, Lining Asian School of the Environment Earth Observatory of Singapore Three‐dimensional Modeling DRNTU::Science::Geology Seismic Velocity Structure We present a new three‐dimensional velocity model of the crust in the eastern margin of the Tibetan Plateau. The model describes the velocity structure of the Sichuan basin and surrounding thrust belts. The model consists of 3‐D surfaces representing major geologic unit contacts and faults and is parameterized with Vp velocity‐depth functions calibrated using sonic logs. The model incorporates data from 1166 oil wells, industry isopach maps, geological maps, and a digital elevation model. The geological surfaces were modeled based on structure contour maps for various units from oil wells and seismic reflection profiles. These surfaces include base Quaternary, Mesozoic, Paleozoic, and Proterozoic horizons. The horizons locally exhibit major offsets that are compatible with the locations and displacements of important faults systems. This layered, upper crustal 3‐D model extends down to 10–15 km depth and illustrates lateral and vertical variations of velocity that reflect the complex evolution of tectonics and sedimentation in the basin. The model also incorporates 3‐D descriptions of Vs and density for sediments that are obtained from empirical relationships with Vp using direct measurements of these properties in borehole logs. To illustrate the impact of our basin model on earthquake hazards assessment, we use it to calculate ground motions and compare these with observations for the 2013 Lushan earthquake. The result demonstrates the effects of basin amplification in the western Sichuan basin. The Sichuan CVM model is intended to facilitate fault systems analysis, strong ground motion prediction, and earthquake hazards assessment for the densely populated Sichuan region. Published version 2018-12-17T02:58:59Z 2019-12-06T17:13:37Z 2018-12-17T02:58:59Z 2019-12-06T17:13:37Z 2016 Journal Article Wang, M., Hubbard, J., Plesch, A., Shaw, J. H., & Wang, L. (2016). Three-dimensional seismic velocity structure in the Sichuan basin, China. Journal of Geophysical Research: Solid Earth, 121(2), 1007-1022. doi:10.1002/2015JB012644 2169-9356 https://hdl.handle.net/10356/88913 http://hdl.handle.net/10220/46982 10.1002/2015JB012644 en Journal of Geophysical Research: Solid Earth © 2016 American Geophysical Union. This paper was published in Journal of Geophysical Research: Solid Earth and is made available as an electronic reprint (preprint) with permission of American Geophysical Union. The published version is available at: [http://dx.doi.org/10.1002/2015JB012644]. 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. 16 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Three‐dimensional Modeling
DRNTU::Science::Geology
Seismic Velocity Structure
spellingShingle Three‐dimensional Modeling
DRNTU::Science::Geology
Seismic Velocity Structure
Wang, Maomao
Hubbard, Judith
Plesch, Andreas
Shaw, John H.
Wang, Lining
Three-dimensional seismic velocity structure in the Sichuan basin, China
description We present a new three‐dimensional velocity model of the crust in the eastern margin of the Tibetan Plateau. The model describes the velocity structure of the Sichuan basin and surrounding thrust belts. The model consists of 3‐D surfaces representing major geologic unit contacts and faults and is parameterized with Vp velocity‐depth functions calibrated using sonic logs. The model incorporates data from 1166 oil wells, industry isopach maps, geological maps, and a digital elevation model. The geological surfaces were modeled based on structure contour maps for various units from oil wells and seismic reflection profiles. These surfaces include base Quaternary, Mesozoic, Paleozoic, and Proterozoic horizons. The horizons locally exhibit major offsets that are compatible with the locations and displacements of important faults systems. This layered, upper crustal 3‐D model extends down to 10–15 km depth and illustrates lateral and vertical variations of velocity that reflect the complex evolution of tectonics and sedimentation in the basin. The model also incorporates 3‐D descriptions of Vs and density for sediments that are obtained from empirical relationships with Vp using direct measurements of these properties in borehole logs. To illustrate the impact of our basin model on earthquake hazards assessment, we use it to calculate ground motions and compare these with observations for the 2013 Lushan earthquake. The result demonstrates the effects of basin amplification in the western Sichuan basin. The Sichuan CVM model is intended to facilitate fault systems analysis, strong ground motion prediction, and earthquake hazards assessment for the densely populated Sichuan region.
author2 Asian School of the Environment
author_facet Asian School of the Environment
Wang, Maomao
Hubbard, Judith
Plesch, Andreas
Shaw, John H.
Wang, Lining
format Article
author Wang, Maomao
Hubbard, Judith
Plesch, Andreas
Shaw, John H.
Wang, Lining
author_sort Wang, Maomao
title Three-dimensional seismic velocity structure in the Sichuan basin, China
title_short Three-dimensional seismic velocity structure in the Sichuan basin, China
title_full Three-dimensional seismic velocity structure in the Sichuan basin, China
title_fullStr Three-dimensional seismic velocity structure in the Sichuan basin, China
title_full_unstemmed Three-dimensional seismic velocity structure in the Sichuan basin, China
title_sort three-dimensional seismic velocity structure in the sichuan basin, china
publishDate 2018
url https://hdl.handle.net/10356/88913
http://hdl.handle.net/10220/46982
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