Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan

Maryline Le Béon, Mong Han Huang, John Suppe, Shiuh Tsann Huang, Erwan Pathier, Wen Jeng Huang, Chien Liang Chen, Bénédicte Fruneau, Stéphane Baize, Kuo-En Ching, Jyr Ching Hu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume28
Issue number5
DOIs
Publication statusPublished - 2017 Oct 1

Fingerprint

geological structure
earthquake
rupture
thrust
geodetic datum
earthquake epicenter
coastal plain
mudstone
crack
GPS
cross section
geology

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)

Cite this

Le Béon, Maryline ; Huang, Mong Han ; Suppe, John ; Huang, Shiuh Tsann ; Pathier, Erwan ; Huang, Wen Jeng ; Chen, Chien Liang ; Fruneau, Bénédicte ; Baize, Stéphane ; Ching, Kuo-En ; Hu, Jyr Ching. / Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan. In: Terrestrial, Atmospheric and Oceanic Sciences. 2017 ; Vol. 28, No. 5.
@article{78e8555bdc8a427fb8c38f176d1a13d7,
title = "Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan",
abstract = "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.",
author = "{Le B{\'e}on}, Maryline and Huang, {Mong Han} and John Suppe and Huang, {Shiuh Tsann} and Erwan Pathier and Huang, {Wen Jeng} and Chen, {Chien Liang} and B{\'e}n{\'e}dicte Fruneau and St{\'e}phane Baize and Kuo-En Ching and Hu, {Jyr Ching}",
year = "2017",
month = "10",
day = "1",
doi = "10.3319/TAO.2017.03.20.02",
language = "English",
volume = "28",
journal = "Terrestrial, Atmospheric and Oceanic Sciences",
issn = "1017-0839",
publisher = "Chinese Geoscience Union",
number = "5",

}

Le Béon, M, Huang, MH, Suppe, J, Huang, ST, Pathier, E, Huang, WJ, Chen, CL, Fruneau, B, Baize, S, Ching, K-E & Hu, JC 2017, 'Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan', Terrestrial, Atmospheric and Oceanic Sciences, vol. 28, no. 5. https://doi.org/10.3319/TAO.2017.03.20.02

Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan. / Le Béon, Maryline; Huang, Mong Han; Suppe, John; Huang, Shiuh Tsann; Pathier, Erwan; Huang, Wen Jeng; Chen, Chien Liang; Fruneau, Bénédicte; Baize, Stéphane; Ching, Kuo-En; Hu, Jyr Ching.

In: Terrestrial, Atmospheric and Oceanic Sciences, Vol. 28, No. 5, 01.10.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Shallow geological structures triggered during the Mw 6.4 Meinong earthquake, southwestern Taiwan

AU - Le Béon, Maryline

AU - Huang, Mong Han

AU - Suppe, John

AU - Huang, Shiuh Tsann

AU - Pathier, Erwan

AU - Huang, Wen Jeng

AU - Chen, Chien Liang

AU - Fruneau, Bénédicte

AU - Baize, Stéphane

AU - Ching, Kuo-En

AU - Hu, Jyr Ching

PY - 2017/10/1

Y1 - 2017/10/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85027833196&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85027833196&partnerID=8YFLogxK

U2 - 10.3319/TAO.2017.03.20.02

DO - 10.3319/TAO.2017.03.20.02

M3 - Article

VL - 28

JO - Terrestrial, Atmospheric and Oceanic Sciences

JF - Terrestrial, Atmospheric and Oceanic Sciences

SN - 1017-0839

IS - 5

ER -