Back to Search
Start Over
Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan
- Source :
- Terrestrial, Atmospheric and Oceanic Sciences, Terrestrial, Atmospheric and Oceanic Sciences, 2017, 28 (5), ⟨10.3319/TAO.2017.03.20.02⟩, Terrestrial, Atmospheric and Oceanic Sciences, Vol 28, Iss 5, Pp 663-681 (2017)
- Publication Year :
- 2017
- Publisher :
- HAL CCSD, 2017.
-
Abstract
- International audience; The Meinong earthquake generated up to ∼10 cm surface displacement located 10-35 km W of the epicenter and monitored by InSAR and GPS. In addition to coseismic deformation related to the deep earthquake source, InSAR revealed three sharp surface displacement gradients. One of them is extensional and is inconsistent with the westward interseismic shortening of ∼45 mm/yr in this region. The gradient sharpness suggests slip triggering on shallow structures, some of which were not well documented before. To characterize these shallow structures, we investigated potential surface ruptures in the field. Sets of ∼NS tension cracks distributed over 25-300 m width, with cumulative extension in the same order as InSAR observations, were found along 5.5 km distance along the extensional gradient and are interpreted as surface rupture. We build two EW regional balanced cross-sections, based on surface geology, subsurface data, and coseismic and interseismic geodetic data. From the Coastal Plain to the E edge of the coseismic deformation area, we propose a series of three active W-dipping back-thrusts the Houchiali fault, the Napalin-Pitou backthrust, and the Lungchuan back-thrust. They all root on the 3.5-4.0 km deep Tainan detachment located near the base of the 3-km-thick Gutingkeng mudstone. Further E, the detachment would ramp down to ∼7 km depth. Coseismic surface deformation measurements suggest that, in addition to the deeper (15-20 km) main rupture plane, mostly the ramp, the Lungchuan back-thrust, and the Tainan detachment were activated during or right after the earthquake. Local extension is considered as transient deformation at the W edge of the shallow main slip zone.
- Subjects :
- Atmospheric Science
geography
geography.geographical_feature_category
010504 meteorology & atmospheric sciences
Deformation (mechanics)
Coastal plain
lcsh:QE1-996.5
lcsh:G1-922
Slip (materials science)
Active fault
Fault (geology)
010502 geochemistry & geophysics
Oceanography
01 natural sciences
lcsh:Geology
[SDU]Sciences of the Universe [physics]
Epicenter
Tension (geology)
Interferometric synthetic aperture radar
Earth and Planetary Sciences (miscellaneous)
Geology
Seismology
lcsh:Geography (General)
0105 earth and related environmental sciences
Subjects
Details
- Language :
- English
- ISSN :
- 10170839
- Database :
- OpenAIRE
- Journal :
- Terrestrial, Atmospheric and Oceanic Sciences, Terrestrial, Atmospheric and Oceanic Sciences, 2017, 28 (5), ⟨10.3319/TAO.2017.03.20.02⟩, Terrestrial, Atmospheric and Oceanic Sciences, Vol 28, Iss 5, Pp 663-681 (2017)
- Accession number :
- edsair.doi.dedup.....a1ef8c4236f768798d69779b75928a75