Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

250 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E PATA Days 2024 K E Y W O R D S Yangsan Fault, Intraplate, paleoearthquake, slip rate, deformation distribution (1) Active Tectonics Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon, Republic of Korea. *Email: adrian0305@kigam.re.kr Taehyung KIM* (1) Jin-Hyuck CHOI (1) Yire CHOI (1) Tae-Ho LEE (1) A PRELIMINARY STUDY ON THE SLIP RATE AND SEISMIC HISTORY OF A PART OF THE YANGSAN FAULT, SE KOREA A B S T R A C T The Yangsan Fault (YF) in SE Korea is a major NNE-SSW oriented intraplate strike-slip fault that has been active since the Cretaceous. The fault shows a predominant dextral strike-slip movement driven by ENE-WSW compressive tectonic stresses since the Quaternary. Despite the absence of historical and instrumental seismic records in Korea, the study aims to uncover paleo-surface ruptures and determine earthquake timings using a multidisciplinary approach. The methods include geomorphic analyses based on vintage aerial photos and high-resolution LiDAR data, coupledwith geophysical explorations like electrical resistivity and seismic refraction surveys. Drilling surveys validate the geomorphic and geophysical findings by identifying the depth of unconformity. Trench excavations at multiple sites along the fault aim to directly observe paleoseismic activity and collect samples for dating. Initial results have identified significant geomorphic offsets indicative of past seismic events. Detailed analysis of these offsets helps estimate the slip rate of the fault over geological timescales. The findings of this study contribute significantly to understanding the seismic history and potential risks associated with the Yangsan Fault. Further studies and dating of the collected samples are expected to refine the timing and recurrence intervals of these past earthquakes. This comprehensive investigation highlights the complex seismic dynamics and ongoing tectonic activity along one of Korea's most significant fault lines. Overall, the research provides crucial insights into the paleoseismology of the region, aiding in better earthquake preparedness and risk management.