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169-6 Seismic Effects of High Density Material in the Southeastern Korean Peninsula: Implications for the Coulomb Failure Stress Change

Session: Advances and Challenges in Seismotectonic Studies in Slow-Deforming Regions

Presenting Author:

Minsu Kim

Authors:

Kim, Minsu¹, So, Byung-Dal², Choe, Hanjin³, Cheon, Youngbeom⁴, Hong Shin, Young⁵, Cho, Hyun‑Moo⁶

(1) Kangwon National University, Chuncheon, Gangwon-do, Korea (The Republic of), (2) Kangwon National University, Chuncheon, Korea (The Republic of), (3) Department of Geological Sciences, Pusan National University, Busan, Korea (The Republic of), (4) Active Tectonics Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon, Korea (The Republic of), (5) Active Tectonics Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon, Korea (The Republic of), (6) Earthquake Research Center, Geology Division, Korea Institute of Geosciences and Mineral Resources, Daejeon, Korea (The Republic of),

Abstract:

The 2016 M_w 5.5 (M_L 5.8) Gyeongju and 2017 M_w 5.5 (M_L 5.4) Pohang earthquake occurred near the Yangsan Fault in the southeastern part of the Korean Peninsula (SKP), where the high Bouguer anomaly was observed. In this study, we investigated the effect of high-density material (HDM) on the local stress state of the SKP, especially on the fault planes of the Pohang and Gyeongju earthquakes and major faults. Through three-dimensional numerical modeling incorporating density structure, obtained by high-resolution gravity inversion data, we analyzed the Coulomb failure stress change (∆CFS) on the faults in the SKP. The presence of HDM significantly affected the local stress field and seismic activity. The high heat flow in the SKP formed the weak viscoelastic strength of the lower crust and upper mantle, amplifying the effect of the HDM. We suggest that the local stress variations and seismic hazard potential are closely related to the subsurface density anomaly. This study provides insights into the importance of considering local geological conditions.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-4766

Seismic Effects of High Density Material in the Southeastern Korean Peninsula: Implications for the Coulomb Failure Stress Change

Description

Session Format: Oral

Presentation Date: 10/21/2025

Presentation Start Time: 09:40 AM

Presentation Room: HBGCC, 217D

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