Shear wave velocity and attenuation structure for the shallow crust of the southern Korean peninsula from short period Rayleigh waves Heeok Jung a, ⁎ , Yong-seok Jang b , Jung Mo Lee c , Wooil M. Moon d , Chang-Eob Baag d , Ki Young Kim e , Bong Gon Jo b a Department of Ocean System Engineering, Kunsan National University, Kunsan, 573-701, South Korea b Department of Earth and Environmental Sciences, ChonBuk National University, JeonJu, South Korea c Department of Geology, Kyungpook National University, Daegu, 702-701, South Korea d School of Earth and Environmental Sciences, Seoul National University, Seoul, 151-742, South Korea e Department of Geophysics, Kangwon National University, Chunchon. 200-701, South Korea Received 4 February 2006; received in revised form 14 October 2006; accepted 16 October 2006 Available online 28 November 2006 Abstract We analyzed the short period Rayleigh waves from the first crustal-scale seismic refraction experiment in the Korean peninsula, KCRUST2002, to determine the shear wave velocity and attenuation structure of the uppermost 1 km of the crust in different tectonic zones of the Korean peninsula and to examine if this can be related to the surface geology of the study area. The experiment was conducted with two large explosive sources along a 300-km long profile in 2002. The seismic traces, recorded on 170 vertical-component, 2-Hz portable seismometers, show distinct Rayleigh waves in the period range between 0.2 s and 1.2 s, which are easily recognizable up to 30–60 km from the sources. The seismic profiles, which traverse three tectonic regions (Gyeonggi massif, Okcheon fold belt and Yeongnam massif), were divided into five subsections based on tectonic boundaries as well as lithology. Group and phase velocities for the five subsections obtained by a continuous wavelet transform method and a slant stack method, respectively, were inverted for the shear wave models. We obtained shear wave velocity models up to a depth of 1.0 km. Overall, the shear wave velocity of the Okcheon fold belt is lower than that of the Gyeonggi and Yeongnam massifs by ∼ 0.4 km/s in the shallowmost 0.2 km and by 0.2 km/s at depths below 0.2 km. Attenuation coefficients, determined from the decay of the fundamental mode Rayleigh waves, were used to obtain the shear wave attenuation structures for three subsections (one for each of the three different tectonic regions). We obtained an average value of Q β − 1 in the upper 0.5 km for each subsection. Q β − 1 for the Okcheon fold belt (∼ 0.026) is approximately three times larger than Q β − 1 for the massif areas (∼ 0.008). The low shear wave velocity in the Okcheon fold belt is consistent with the high attenuation in this region. © 2006 Elsevier B.V. All rights reserved. Keywords: Shear wave velocity structure; Shear wave attenuation structure; Rayleigh waves; Upper crust 1. Introduction The seismic refraction method has been widely used to investigate the velocity structure of the crust and upper mantle. Whereas travel times and amplitudes of seismic refraction data are useful for modeling the Tectonophysics 429 (2007) 253 – 265 www.elsevier.com/locate/tecto ⁎ Corresponding author. Tel./fax: +82 63 469 1750. E-mail addresses: hjjung@kunsan.ac.kr (H. Jung), divergence@chonbuk.ac.kr (Y. Jang), jung@knu.ac.kr (J.M. Lee), wmoon@eos1.snu.ac.kr (W.M. Moon), baagce@snu.ac.kr (C.-E. Baag), kykim@kangwon.ac.kr (K.Y. Kim), bgjo@chonbuk.ac.kr (B.G. Jo). 0040-1951/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.tecto.2006.10.003