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Seismic Velocity Structure Along the KCRT-2008 Profile using Traveltime Inversion of First Arrivals  

Kim, Ki-Young (Department of Geophysics, Kangwon National University)
Lee, Jung-Mo (Department of Geology, Kyungpook National University)
Baag, Chang-Eob (School of Earth & Environmental Sciences, Seoul National University)
Jung, Hee-Ok (Department of Ocean System Engineering, Kunsan National University)
Hong, Myung-Ho (Department of Geophysics, Kangwon National University)
Kim, Jun-Yeong (Department of Geophysics, Kangwon National University)
Publication Information
Geophysics and Geophysical Exploration / v.13, no.2, 2010 , pp. 153-158 More about this Journal
Abstract
To investigate the velocity structure in the central and southern parts of the Korean peninsula, a 299-km NW-SE seismic refraction profile KCRT-2008was obtained across major tectonic boundaries. Seismic waves were generated by detonating 250 ~ 1500 kg explosives at depths of 50 ~ 100 m in eight drill holes located at intervals of 21 ~ 113 km. The seismic signals were detected by 4.5 Hz geophones at a nominal interval of 500 m. The first-arrival times were inverted to derive a velocity tomogram. The raypaths indicate several mid-crust interfaces including those at approximate depths of 2 ~ 3, 11 ~ 13, and 20 km. The Moho discontinuity with refraction velocity of 7.7 to 8.1 km/s has a maximum depth of 34.5 km under the central portion of the peninsula. The Moho becomes shallower as the Yellow Sea and the East Sea are approached on the west and east coasts of the peninsula, respectively. The depth of the 7.6 km/s velocity contour varies from 31.3 km to 34.4 km. The velocity tomogram shows the existence of a 129 km wide low-velocity zone centered at 7.2 km depth under the Okchon fold belt and Gyeonggi massif and low-velocity(< 5.4 km/s) rocks in the Gyeongsang sedimentary basin with a maximum thickness of 2.6 km
Keywords
velocity structure; seismic experiment; first-arrival times; tomography; Moho;
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Times Cited By KSCI : 1  (Citation Analysis)
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