TY - JOUR
T1 - A multidisciplinary approach to characterization of the mature northern Yangsan fault in Korea and its active faulting
AU - Ko, Kyoungtae
AU - Choi, Sung Ja
AU - Lee, Tae Ho
AU - Gihm, Yong Sik
AU - Kim, Chang Min
AU - Kim, Kiju
AU - Cheon, Youngbeom
N1 - Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature B.V.
PY - 2022/6
Y1 - 2022/6
N2 - Some parts of the Yangsan Fault, a prominent mature intraplate fault on the Korean Peninsula, are still active. However, structural and paleoseismic investigations are limited because a large portion of the fault zone is covered by Quaternary sediments. To characterize the northern Yangsan Fault (NYF) and its paleoseismic features, we conducted topographic analyses, geological mapping, electrical resistivity surveys, borehole drilling, SHRIMP U–Pb age dating, a trench survey, and optically-stimulated-luminescence age dating (OSL). This multidisciplinary approach shows that the NYF is expressed as a nearly straight incised valley and a ridge-disrupting topographic lineament with anastomosing multiple core zones at outcrops. The NYF in Yeonghae area exhibits a NNE-striking eastern strand and a NNW- to N–S-striking western strand. Between these, a Jurassic granite (> 300-m-wide) is distributed as an enclosed lens, bounded by Precambrian metamorphic rocks to the east and Cretaceous sedimentary rocks to the west. The eastern strand likely passes S–N through the offshore area (East Sea) to onshore Pyeonghae area. A trench survey identified faults transecting Quaternary strata, providing the first paleoseismic record along the NYF. Stratigraphic features and OSL ages show that the most recent rupture occurred after 97 ± 7 ka, with the rupture along the western boundary of the mature fault core. Although older structures are prominent, paleoseismic records are few—a limitation for our onshore investigations. To reveal YF neotectonic activities under the East Sea, we need further information about off-fault damage (landslide, turbidite, tsunami records) within marine deposits as well as on-fault damage.
AB - Some parts of the Yangsan Fault, a prominent mature intraplate fault on the Korean Peninsula, are still active. However, structural and paleoseismic investigations are limited because a large portion of the fault zone is covered by Quaternary sediments. To characterize the northern Yangsan Fault (NYF) and its paleoseismic features, we conducted topographic analyses, geological mapping, electrical resistivity surveys, borehole drilling, SHRIMP U–Pb age dating, a trench survey, and optically-stimulated-luminescence age dating (OSL). This multidisciplinary approach shows that the NYF is expressed as a nearly straight incised valley and a ridge-disrupting topographic lineament with anastomosing multiple core zones at outcrops. The NYF in Yeonghae area exhibits a NNE-striking eastern strand and a NNW- to N–S-striking western strand. Between these, a Jurassic granite (> 300-m-wide) is distributed as an enclosed lens, bounded by Precambrian metamorphic rocks to the east and Cretaceous sedimentary rocks to the west. The eastern strand likely passes S–N through the offshore area (East Sea) to onshore Pyeonghae area. A trench survey identified faults transecting Quaternary strata, providing the first paleoseismic record along the NYF. Stratigraphic features and OSL ages show that the most recent rupture occurred after 97 ± 7 ka, with the rupture along the western boundary of the mature fault core. Although older structures are prominent, paleoseismic records are few—a limitation for our onshore investigations. To reveal YF neotectonic activities under the East Sea, we need further information about off-fault damage (landslide, turbidite, tsunami records) within marine deposits as well as on-fault damage.
KW - Active fault
KW - Intraplate mature fault
KW - Multiple core zones
KW - Northern Yangsan fault
UR - http://www.scopus.com/inward/record.url?scp=85130873171&partnerID=8YFLogxK
U2 - 10.1007/s11001-022-09486-w
DO - 10.1007/s11001-022-09486-w
M3 - Article
AN - SCOPUS:85130873171
SN - 0025-3235
VL - 43
JO - Marine Geophysical Researches
JF - Marine Geophysical Researches
IS - 2
M1 - 21
ER -