169 Advances and Challenges in Seismotectonic Studies in Slow-Deforming Regions
This session explores advances and challenges in understanding tectonic deformation in slow-deforming regions, integrating geodetic, geological, and modeling approaches to address earthquake hazards in seemingly stable yet vulnerable intraplate settings.
Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 217D
Seismic Effects of High Density Material in the Southeastern Korean Peninsula: Implications for the Coulomb Failure Stress Change
Paper number: 169-7
Program: Technical Sessions
Time: 9:40 AM – 9:55 AM
Authors
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Byung-Dal SoKangwon National University, Chuncheon
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Hanjin ChoePusan National University, Busan
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Youngbeom CheonKorea Institute of Geoscience and Mineral Resources, Daejeon
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Young Hong ShinKorea Institute of Geoscience and Mineral Resources, Daejeon
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Hyun‑Moo ChoGeology Division, Korea Institute of Geosciences and Mineral Resources, Daejeon
Abstract
The 2016 Mw 5.5 (ML 5.8) Gyeongju and 2017 Mw 5.5 (ML 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 Programs. Vol. 57, No. 6
doi: 10.1130/abs/2025AM-411996
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