Estimation of surface-wave phase velocities and attenuation coefficients in southern Korea from spatial coherency of the ambient seismic noise

The measurements of the spatial coherency of the ambient seismic noise as a function of interstation distance produce distribution of surface-wave phase velocities and attenuation coefficients in southern Korea. The coherency pairs from 43 broadband stations are used for the estimation of phase velocity and attenuation coefficient in the period band of 5 - 20 seconds. From these measurements we simultaneously invert 1-D shear wave velocity and Q as a function of depth beneath southern Korea. To investigate localized velocities and attenuations associated with tectonic units, we subdivide the measurements according to the interstation paths. We retrieve lower-wave velocities and lower-quality factors in the Gyeongsang basin, Cretaceous nonmarine basin in the southeastern area.