The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake

Possible short-term precursors several days before the Taiwan Chi-Chi earthquake (Mw = 7.6) on 20 September 1999 were observed by examining crustal deformation that were directly integrated from broadband velocity seismograms. Significant deviations of the vertical displacement from a normal Earth t...

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Main Author: Cheng-Horng Lin
Format: Article
Language:English
Published: Springer 2012-01-01
Series:Terrestrial, Atmospheric and Oceanic Sciences
Subjects:
Online Access: http://tao.cgu.org.tw/images/attachments/v232p145.pdf
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author Cheng-Horng Lin
author_facet Cheng-Horng Lin
author_sort Cheng-Horng Lin
collection DOAJ
description Possible short-term precursors several days before the Taiwan Chi-Chi earthquake (Mw = 7.6) on 20 September 1999 were observed by examining crustal deformation that were directly integrated from broadband velocity seismograms. Significant deviations of the vertical displacement from a normal Earth tidal pattern on 15 - 19 September show some tiny surface crustal deformation having taken place several days in advance of the earthquake on 20 September. A series of slow slip events on the nearly horizontal plane (or decollement) at depths between 10 and 12 km provide a possible explanation for generating the anomalous crustal deformations before the earthquake. Although those slow slip events are not well constrained owing to limited observations at only two broadband seismic stations, their possibility is acceptable from a geological standpoint if the decollement beneath central Taiwan can be evidenced from both geological and geodetic studies. However, no matter what the exact mechanism was which generated the irregular earth tidal deformation several days before the 1999 Taiwan Chi-Chi earthquake, these anomalous crustal deformations might be considered to be possible short-term earthquake precursors.
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spelling doaj.art-61c75fe55cd14128897e3428d47a68932022-12-22T02:57:03ZengSpringerTerrestrial, Atmospheric and Oceanic Sciences1017-08392311-76802012-01-0123214510.3319/TAO.2011.09.23.01(T)1058The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi EarthquakeCheng-Horng LinPossible short-term precursors several days before the Taiwan Chi-Chi earthquake (Mw = 7.6) on 20 September 1999 were observed by examining crustal deformation that were directly integrated from broadband velocity seismograms. Significant deviations of the vertical displacement from a normal Earth tidal pattern on 15 - 19 September show some tiny surface crustal deformation having taken place several days in advance of the earthquake on 20 September. A series of slow slip events on the nearly horizontal plane (or decollement) at depths between 10 and 12 km provide a possible explanation for generating the anomalous crustal deformations before the earthquake. Although those slow slip events are not well constrained owing to limited observations at only two broadband seismic stations, their possibility is acceptable from a geological standpoint if the decollement beneath central Taiwan can be evidenced from both geological and geodetic studies. However, no matter what the exact mechanism was which generated the irregular earth tidal deformation several days before the 1999 Taiwan Chi-Chi earthquake, these anomalous crustal deformations might be considered to be possible short-term earthquake precursors. http://tao.cgu.org.tw/images/attachments/v232p145.pdf Slow slipEarthquake precursorChi-Chi earthquakeTidal deformation
spellingShingle Cheng-Horng Lin
The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
Terrestrial, Atmospheric and Oceanic Sciences
Slow slip
Earthquake precursor
Chi-Chi earthquake
Tidal deformation
title The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
title_full The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
title_fullStr The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
title_full_unstemmed The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
title_short The Possible Observation of Slow Slip Events Prior to the Occurrence of the 1999 Chi-Chi Earthquake
title_sort possible observation of slow slip events prior to the occurrence of the 1999 chi chi earthquake
topic Slow slip
Earthquake precursor
Chi-Chi earthquake
Tidal deformation
url http://tao.cgu.org.tw/images/attachments/v232p145.pdf
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