Direct estimation of near-surface damping based on normalized energy density

Abstract

We propose a direct estimation of dampings in surface layers based on the normalized energy density (NED). The ratio of the NED, defined as the NED for the uppermost layer divided by the NED for the basement, correlates well with the total damping, t^∗_S. We apply the relation between the NED ratio and the total damping to estimate the total damping at an actual site, Katagihara (KTG) site in Japan. The total damping at the KTG site is directly estimated as t^∗_S=0.038. This value agrees well with the estimated values determined from a conventional method, incorporating the non-linear inversion scheme.