The crustal deformation of the Ilan Plain acted as a westernmost extension of the Okinawa Trough

Chin Shyong Hou, Jyr Ching Hu, Kuo-En Ching, Yue Gau Chen, Chien Liang Chen, Li Wei Cheng, Chao Lung Tang, Shin Hua Huang, Ching Hua Lo

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Abstract

We analyze the current deformation in Ilan Plain of northeastern Taiwan considered as the western extension of Okinawa Trough based on 34 geodetic sites observed between 2002 and 2006. The station velocities are between 1.9 mm/yr and 43.0 mm/yr in a direction between 38 ° and 143 ° relative to stable continent margin of Eurasian plate. This largest velocity is moving southeastward (143 °) at a rate of ~ 43 mm/yr was enhanced by a seismic doublet that occurred on March 6, 2005. The station velocities at the northern margin of Ilan Plain are insignificant with a magnitude of ~ 1.9 mm/yr to ~ 7.5 mm/yr. On the contrary, the station velocities increase approximately southward along the southern margin of Ilan Plain. The stations are moving roughly E-W with a magnitude of ~ 5.8 mm/yr to ~ 21.8 mm/yr. Further southward, the station velocities increase to a value of ~ 43.0 mm/yr in a direction of 143 °. The most prominent feature of the strain distribution patterns in Ilan Plain are the remarkable extensional strain rates observed in central and southern flank of the Ilan Plain. The largest extensional rate is found (2.66 μstrain/yr in 147°) with a shortening rate in the perpendicular direction (1.28 μstrain/yr in 57°), indicating transtensional deformation mode. In the northeastern flank of Ilan Plain, insignificant or minor deformations are observed. Overall the extensional rates in this area clearly increase from north to south. The extension directions in study area mostly trend E-W to NW-SE directions. Using the velocity field of 34 GPS stations and its strain rate filed, we suggest the lateral extrusion process towards mechanically weak domain adjacent Ryukyu subduction zone. The lateral extrusion is facilitated by the opening of the Okinawa Trough. We conclude that the northeast Taiwan is subjected to both the compressional force exerted by the indentation of Philippine Sea plate and the tensile force induced by trench retreat related to the suction force at the Ryukyu trench. Due to the interaction of two forces, the stress regime rapidly changes from pure compression in the Taiwan collision belt to transtension near Ilan Plain and its offshore area.

Original languageEnglish
Pages (from-to)344-355
Number of pages12
JournalTectonophysics
Volume466
Issue number3-4
DOIs
Publication statusPublished - 2009 Mar 10

Fingerprint

crustal deformation
plains
troughs
trough
stations
Taiwan
margins
extrusion
strain rate
trench
transtension
Philippines
Philippine Sea plate
indentation
strain distribution
Eurasian plate
suction
continents
plain
subduction zone

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth-Surface Processes

Cite this

Hou, Chin Shyong ; Hu, Jyr Ching ; Ching, Kuo-En ; Chen, Yue Gau ; Chen, Chien Liang ; Cheng, Li Wei ; Tang, Chao Lung ; Huang, Shin Hua ; Lo, Ching Hua. / The crustal deformation of the Ilan Plain acted as a westernmost extension of the Okinawa Trough. In: Tectonophysics. 2009 ; Vol. 466, No. 3-4. pp. 344-355.
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abstract = "We analyze the current deformation in Ilan Plain of northeastern Taiwan considered as the western extension of Okinawa Trough based on 34 geodetic sites observed between 2002 and 2006. The station velocities are between 1.9 mm/yr and 43.0 mm/yr in a direction between 38 ° and 143 ° relative to stable continent margin of Eurasian plate. This largest velocity is moving southeastward (143 °) at a rate of ~ 43 mm/yr was enhanced by a seismic doublet that occurred on March 6, 2005. The station velocities at the northern margin of Ilan Plain are insignificant with a magnitude of ~ 1.9 mm/yr to ~ 7.5 mm/yr. On the contrary, the station velocities increase approximately southward along the southern margin of Ilan Plain. The stations are moving roughly E-W with a magnitude of ~ 5.8 mm/yr to ~ 21.8 mm/yr. Further southward, the station velocities increase to a value of ~ 43.0 mm/yr in a direction of 143 °. The most prominent feature of the strain distribution patterns in Ilan Plain are the remarkable extensional strain rates observed in central and southern flank of the Ilan Plain. The largest extensional rate is found (2.66 μstrain/yr in 147°) with a shortening rate in the perpendicular direction (1.28 μstrain/yr in 57°), indicating transtensional deformation mode. In the northeastern flank of Ilan Plain, insignificant or minor deformations are observed. Overall the extensional rates in this area clearly increase from north to south. The extension directions in study area mostly trend E-W to NW-SE directions. Using the velocity field of 34 GPS stations and its strain rate filed, we suggest the lateral extrusion process towards mechanically weak domain adjacent Ryukyu subduction zone. The lateral extrusion is facilitated by the opening of the Okinawa Trough. We conclude that the northeast Taiwan is subjected to both the compressional force exerted by the indentation of Philippine Sea plate and the tensile force induced by trench retreat related to the suction force at the Ryukyu trench. Due to the interaction of two forces, the stress regime rapidly changes from pure compression in the Taiwan collision belt to transtension near Ilan Plain and its offshore area.",
author = "Hou, {Chin Shyong} and Hu, {Jyr Ching} and Kuo-En Ching and Chen, {Yue Gau} and Chen, {Chien Liang} and Cheng, {Li Wei} and Tang, {Chao Lung} and Huang, {Shin Hua} and Lo, {Ching Hua}",
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Hou, CS, Hu, JC, Ching, K-E, Chen, YG, Chen, CL, Cheng, LW, Tang, CL, Huang, SH & Lo, CH 2009, 'The crustal deformation of the Ilan Plain acted as a westernmost extension of the Okinawa Trough', Tectonophysics, vol. 466, no. 3-4, pp. 344-355. https://doi.org/10.1016/j.tecto.2007.11.022

The crustal deformation of the Ilan Plain acted as a westernmost extension of the Okinawa Trough. / Hou, Chin Shyong; Hu, Jyr Ching; Ching, Kuo-En; Chen, Yue Gau; Chen, Chien Liang; Cheng, Li Wei; Tang, Chao Lung; Huang, Shin Hua; Lo, Ching Hua.

In: Tectonophysics, Vol. 466, No. 3-4, 10.03.2009, p. 344-355.

Research output: Contribution to journalArticle

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T1 - The crustal deformation of the Ilan Plain acted as a westernmost extension of the Okinawa Trough

AU - Hou, Chin Shyong

AU - Hu, Jyr Ching

AU - Ching, Kuo-En

AU - Chen, Yue Gau

AU - Chen, Chien Liang

AU - Cheng, Li Wei

AU - Tang, Chao Lung

AU - Huang, Shin Hua

AU - Lo, Ching Hua

PY - 2009/3/10

Y1 - 2009/3/10

N2 - We analyze the current deformation in Ilan Plain of northeastern Taiwan considered as the western extension of Okinawa Trough based on 34 geodetic sites observed between 2002 and 2006. The station velocities are between 1.9 mm/yr and 43.0 mm/yr in a direction between 38 ° and 143 ° relative to stable continent margin of Eurasian plate. This largest velocity is moving southeastward (143 °) at a rate of ~ 43 mm/yr was enhanced by a seismic doublet that occurred on March 6, 2005. The station velocities at the northern margin of Ilan Plain are insignificant with a magnitude of ~ 1.9 mm/yr to ~ 7.5 mm/yr. On the contrary, the station velocities increase approximately southward along the southern margin of Ilan Plain. The stations are moving roughly E-W with a magnitude of ~ 5.8 mm/yr to ~ 21.8 mm/yr. Further southward, the station velocities increase to a value of ~ 43.0 mm/yr in a direction of 143 °. The most prominent feature of the strain distribution patterns in Ilan Plain are the remarkable extensional strain rates observed in central and southern flank of the Ilan Plain. The largest extensional rate is found (2.66 μstrain/yr in 147°) with a shortening rate in the perpendicular direction (1.28 μstrain/yr in 57°), indicating transtensional deformation mode. In the northeastern flank of Ilan Plain, insignificant or minor deformations are observed. Overall the extensional rates in this area clearly increase from north to south. The extension directions in study area mostly trend E-W to NW-SE directions. Using the velocity field of 34 GPS stations and its strain rate filed, we suggest the lateral extrusion process towards mechanically weak domain adjacent Ryukyu subduction zone. The lateral extrusion is facilitated by the opening of the Okinawa Trough. We conclude that the northeast Taiwan is subjected to both the compressional force exerted by the indentation of Philippine Sea plate and the tensile force induced by trench retreat related to the suction force at the Ryukyu trench. Due to the interaction of two forces, the stress regime rapidly changes from pure compression in the Taiwan collision belt to transtension near Ilan Plain and its offshore area.

AB - We analyze the current deformation in Ilan Plain of northeastern Taiwan considered as the western extension of Okinawa Trough based on 34 geodetic sites observed between 2002 and 2006. The station velocities are between 1.9 mm/yr and 43.0 mm/yr in a direction between 38 ° and 143 ° relative to stable continent margin of Eurasian plate. This largest velocity is moving southeastward (143 °) at a rate of ~ 43 mm/yr was enhanced by a seismic doublet that occurred on March 6, 2005. The station velocities at the northern margin of Ilan Plain are insignificant with a magnitude of ~ 1.9 mm/yr to ~ 7.5 mm/yr. On the contrary, the station velocities increase approximately southward along the southern margin of Ilan Plain. The stations are moving roughly E-W with a magnitude of ~ 5.8 mm/yr to ~ 21.8 mm/yr. Further southward, the station velocities increase to a value of ~ 43.0 mm/yr in a direction of 143 °. The most prominent feature of the strain distribution patterns in Ilan Plain are the remarkable extensional strain rates observed in central and southern flank of the Ilan Plain. The largest extensional rate is found (2.66 μstrain/yr in 147°) with a shortening rate in the perpendicular direction (1.28 μstrain/yr in 57°), indicating transtensional deformation mode. In the northeastern flank of Ilan Plain, insignificant or minor deformations are observed. Overall the extensional rates in this area clearly increase from north to south. The extension directions in study area mostly trend E-W to NW-SE directions. Using the velocity field of 34 GPS stations and its strain rate filed, we suggest the lateral extrusion process towards mechanically weak domain adjacent Ryukyu subduction zone. The lateral extrusion is facilitated by the opening of the Okinawa Trough. We conclude that the northeast Taiwan is subjected to both the compressional force exerted by the indentation of Philippine Sea plate and the tensile force induced by trench retreat related to the suction force at the Ryukyu trench. Due to the interaction of two forces, the stress regime rapidly changes from pure compression in the Taiwan collision belt to transtension near Ilan Plain and its offshore area.

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