Reactivated Timings of Yangsan Fault in the Sangcheon-ri Area, Korea

Abstract

Here we firstly present that a timing of reactivated event of Yangsan fault, the major fault in the southeastern Korean Peninsula, by using combined approaches of the optimized illite-polytype quantification, the K-Ar age-dating, and the recently developed illite-age-analysis (IAA) approach for the fault clays from Sangcheon-ri area of Yangsan main fault line. Two chronological record of brittle fault-activation event at about 41.5~43.5 and 50.7 Ma were determined from 3 fault gouges suggesting a crucial reactivation time-scheme. Furthermore, the regional processes that drive tectonics to form and reactivate the Yangsan fault may be explained from the chronological analysis for additional sites along the Yangsan fault.

3D Fabric Analysis in Fault Rock Using Synchrotron μ-CT: A Statistical Approach to SPO (Shape Preferred Orientation) for Estimation of Fault Motion

“…Since the Cretaceous, the Yangsan fault has been activated at least twice due to large events, such as the collision of the Indian Plate and the opening of the East Sea (Japan Sea) [18]. From K-Ar illite dating for the area where the main fault line of Yangsan fault penetrates, the fault activation ages of 19.6 and 26.1-27.9 Ma for the Bogyeongsa area in the northern part, and 41.5-43.5 and 50.7 Ma for the Sangcheon-ri area in the middle part have been reported [19,20]. In addition, the tectonic environment affecting the Yangsan fault zone is different for each period.…”

“…Therefore, the limitations of the previous study were supplemented and information about intermediate and minor axes was extracted to obtain additional strain information. Previous studies have been conducted to investigate AMS that acquired information on the magnetic susceptibility of rocks, which was a similar concept to that used in this study [20,23,[36][37][38]. The AMS ellipsoid of the rock was calculated by measuring the strength according to the orientation of magnetic susceptibility at least six times, and the strain was analyzed using the orientation and crystallographic characteristics of the major, intermediate, and minor axes [39].…”

Reactivated Timings of Yangsan Fault in the Northern Pohang Area, Korea

“…국내에서는 최근 Chung et al, 2014;Khulganakhuu et al, 2015). (Song et al, , 2016Chung et al, 2013Chung et al, , 2014Khulganakhuu et al, 2015). (Song et al, , 2016Chung et al, 2013Chung et al, , 2014Khulganakhuu et al, 2015).…”

“…(Song et al, , 2016Chung et al, 2013Chung et al, , 2014Khulganakhuu et al, 2015). (Song et al, , 2016Chung et al, 2013Chung et al, , 2014Khulganakhuu et al, 2015). 33° 2θ 간격의 피크를 대상으로 WILDFIREC 시뮬레 이션 (Reynolds, 1994) (Chung et al, 2013).…”

“…4) Vrolijk and van der Pluijm, 1999;Grathoff et al, 2001). 이 같은 결과는 기존의 천부단층점토를 대상으 로 수행한 국외 연구결과 (Pevear, 1992(Pevear, , 1999van der Pluijm et al, 2001van der Pluijm et al, , 2006Solum et al, 2005;Haines and van der Pluijm, 2008;Schleicher et al, 2010;Duvall et al, 2011;Rahl et al, 2011) 및 최근 수행된 국내 연구결과 (Song et al, , 2016Chung et al, 2014;Khulganakhuu et al, 2015) (Srodon and Eberl, 1984;Alt and Jiang, 1991;Inoue et al, 1992;Kuwahara et. al., 1998Kuwahara et.…”