Three-Dimensional Pore Fluid Pressures in Source Region of 2017 Pohang Earthquake Inferred From Earthquake Focal Mechanisms

Toshiko Terakawa; Wooseok Seo; Kwang Hee Kim; Jin Han Ree

doi:10.1029/2019GL085964

Three-Dimensional Pore Fluid Pressures in Source Region of 2017 Pohang Earthquake Inferred From Earthquake Focal Mechanisms

Toshiko Terakawa^*
, Wooseok Seo
, Kwang Hee Kim
, Jin Han Ree

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

21 Citations (Scopus)

Abstract

We analyzed 91 focal mechanism data with relocated hypocenters to estimate the 3-D pore fluid pressure field in the source region of the 2017 Pohang earthquake in South Korea using the method of focal mechanism tomography. The upper limit of pore fluid pressure was 8 ± 3 MPa in a location northwest of the enhanced geothermal system. The overpressurized fluids were localized in the footwall of the causative fault. It was directly connected to the open hole section of PX2, and fluid injection into this hole could have triggered the mainshock.

Original language	English
Article number	e2019GL085964
Journal	Geophysical Research Letters
Volume	47
Issue number	9
DOIs	https://doi.org/10.1029/2019GL085964
Publication status	Published - 2020 May 16

Bibliographical note

Publisher Copyright:
©2020. The Authors.

Keywords

Pohang earthquake
earthquake focal mechanism
friction coefficient
inversion analysis
pore fluid pressure
stress

ASJC Scopus subject areas

Geophysics
General Earth and Planetary Sciences

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10.1029/2019GL085964

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title = "Three-Dimensional Pore Fluid Pressures in Source Region of 2017 Pohang Earthquake Inferred From Earthquake Focal Mechanisms",

abstract = "We analyzed 91 focal mechanism data with relocated hypocenters to estimate the 3-D pore fluid pressure field in the source region of the 2017 Pohang earthquake in South Korea using the method of focal mechanism tomography. The upper limit of pore fluid pressure was 8 ± 3 MPa in a location northwest of the enhanced geothermal system. The overpressurized fluids were localized in the footwall of the causative fault. It was directly connected to the open hole section of PX2, and fluid injection into this hole could have triggered the mainshock.",

keywords = "Pohang earthquake, earthquake focal mechanism, friction coefficient, inversion analysis, pore fluid pressure, stress",

author = "Toshiko Terakawa and Wooseok Seo and Kim, \{Kwang Hee\} and Ree, \{Jin Han\}",

note = "Publisher Copyright: {\textcopyright}2020. The Authors.",

year = "2020",

month = may,

day = "16",

doi = "10.1029/2019GL085964",

language = "English",

volume = "47",

journal = "Geophysical Research Letters",

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AU - Terakawa, Toshiko

AU - Seo, Wooseok

AU - Kim, Kwang Hee

AU - Ree, Jin Han

PY - 2020/5/16

Y1 - 2020/5/16

N2 - We analyzed 91 focal mechanism data with relocated hypocenters to estimate the 3-D pore fluid pressure field in the source region of the 2017 Pohang earthquake in South Korea using the method of focal mechanism tomography. The upper limit of pore fluid pressure was 8 ± 3 MPa in a location northwest of the enhanced geothermal system. The overpressurized fluids were localized in the footwall of the causative fault. It was directly connected to the open hole section of PX2, and fluid injection into this hole could have triggered the mainshock.

AB - We analyzed 91 focal mechanism data with relocated hypocenters to estimate the 3-D pore fluid pressure field in the source region of the 2017 Pohang earthquake in South Korea using the method of focal mechanism tomography. The upper limit of pore fluid pressure was 8 ± 3 MPa in a location northwest of the enhanced geothermal system. The overpressurized fluids were localized in the footwall of the causative fault. It was directly connected to the open hole section of PX2, and fluid injection into this hole could have triggered the mainshock.

KW - Pohang earthquake

KW - earthquake focal mechanism

KW - friction coefficient

KW - inversion analysis

KW - pore fluid pressure

KW - stress

UR - https://www.scopus.com/pages/publications/85084454961

U2 - 10.1029/2019GL085964

DO - 10.1029/2019GL085964

M3 - Article

AN - SCOPUS:85084454961

SN - 0094-8276

VL - 47

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 9

M1 - e2019GL085964

ER -

Three-Dimensional Pore Fluid Pressures in Source Region of 2017 Pohang Earthquake Inferred From Earthquake Focal Mechanisms

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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