Applications of soft-sediment deformation structures in paleoseismology

초록

Following the 2016 Gyeongju and 2017 Pohang earthquakes, the importance of preventing earthquake disasters became clear, leading to widespread investigations of active faults and paleoearthquake studies throughout South Korea. Paleoseismic research utilizes various geological structures, including surface ruptures, and one such structure is seismically-induced soft-sediment deformation structures (SSDS). These structures are formed when unconsolidated sediments lose their shear strength and undergo deformation due to liquefaction, rendering them susceptible to deformation even under minor stress. SSDS can indirectly indicate the timing, recurrence interval, magnitude, and epicenter of the triggering earthquake. Compared to surface ruptures, SSDS can form under events of lower magnitude events and are more likely to be preserved. However, studies on Quaternary seismic SSDS in Korea remain limited. To explore the potential application of these methodologies to paleoseismic studies in the Korean Peninsula, this study analyzes case studies from the Dead Sea Basin in Israel and the Concud Fault in Spain, where in-depth quantitative analysis and borehole investigations of seismic SSDS have been carried out. The application of these research methods to domestic active fault investigations is expected to enable more precise paleoseismic studies and enhance earthquake hazard assessments in South Korea.

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