Fault geometries illuminated from seismicity in central Taiwan: Implications for crustal scale structural boundaries in the northern Central Range

Jonathan R. Gourley, Timothy Byrne, Yu Chang Chan, Francis Wu, Ruey Juin Rau

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Data sets of collapsed earthquake locations, earthquake focal mechanisms, GPS velocities and geologic data are integrated to constrain the geometry and kinematics of a crustal block within the accreted continental margin rocks of Taiwan's northeastern Central Range. This block is laterally extruding and exhuming towards the north-northeast. The block is bound on the west-southwest by the previously recognized Sanyi-Puli seismic zone and on the east by a vertical seismic structure that projects to the eastern mountain front of the Central Range. Focal mechanisms from the Broadband Array of Taiwan Seismicity (BATS) catalog consistently show west-side-up reverse displacements for this fault zone. A second vertical structure is recognized beneath the Slate Belt-Metamorphic Belt boundary as a post-Chi-Chi relaxation oblique normal fault. BATS focal mechanisms show east-side-up, normal displacements with a minor left-lateral component. The vertical and lateral extrusion of this crustal block may be driven by the current collision between the Philippine Sea Plate and the Puli basement high indenter on the Eurasian Plate and/or trench rollback along the Ryukyu subduction zone. In addition, the vertical extent of the two shear zones suggests that a basal décollement below the eastern Central Range is deeper than previously proposed and may extend below the brittle-ductile transition.

Original languageEnglish
Pages (from-to)168-185
Number of pages18
JournalTectonophysics
Volume445
Issue number3-4
DOIs
Publication statusPublished - 2007 Dec 20

Fingerprint

fault geometry
Taiwan
focal mechanism
seismicity
earthquakes
geometry
extruding
oblique fault
broadband
ductile-brittle transition
earthquake
Philippines
Philippine Sea plate
slate
Eurasian plate
seismic zone
continental shelves
extrusion
basements
mountains

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth-Surface Processes

Cite this

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title = "Fault geometries illuminated from seismicity in central Taiwan: Implications for crustal scale structural boundaries in the northern Central Range",
abstract = "Data sets of collapsed earthquake locations, earthquake focal mechanisms, GPS velocities and geologic data are integrated to constrain the geometry and kinematics of a crustal block within the accreted continental margin rocks of Taiwan's northeastern Central Range. This block is laterally extruding and exhuming towards the north-northeast. The block is bound on the west-southwest by the previously recognized Sanyi-Puli seismic zone and on the east by a vertical seismic structure that projects to the eastern mountain front of the Central Range. Focal mechanisms from the Broadband Array of Taiwan Seismicity (BATS) catalog consistently show west-side-up reverse displacements for this fault zone. A second vertical structure is recognized beneath the Slate Belt-Metamorphic Belt boundary as a post-Chi-Chi relaxation oblique normal fault. BATS focal mechanisms show east-side-up, normal displacements with a minor left-lateral component. The vertical and lateral extrusion of this crustal block may be driven by the current collision between the Philippine Sea Plate and the Puli basement high indenter on the Eurasian Plate and/or trench rollback along the Ryukyu subduction zone. In addition, the vertical extent of the two shear zones suggests that a basal d{\'e}collement below the eastern Central Range is deeper than previously proposed and may extend below the brittle-ductile transition.",
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Fault geometries illuminated from seismicity in central Taiwan : Implications for crustal scale structural boundaries in the northern Central Range. / Gourley, Jonathan R.; Byrne, Timothy; Chan, Yu Chang; Wu, Francis; Rau, Ruey Juin.

In: Tectonophysics, Vol. 445, No. 3-4, 20.12.2007, p. 168-185.

Research output: Contribution to journalArticle

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