Secondary Love Waves Observed by a Strong-Motion Array in the Tokyo Lowlands, Japan

Abstract

In order to investigate the generation and propagation of Love waves recorded in the Tokyo lowlands, we analyzed array data obtained for six events that occurred around the Kanto district. From wavenumber analysis, the following conclusions are obtained. (1) Love waves are converted from direct S-waves at the edge of a sedimentary basin. The Hachiohji tectonic line is an especially important zone for the generation of Love waves. (2) Apparent velocities of Love waves for periods between 6 and 9 s are concordant with the phase velocities of fundamental mode Love waves calculated from a three-layered model. The first, second, and third layers in the model have S-wave velocities of 0.5, 0.8, and 1.2km/s, respectively. The S-wave velocity in the pre-Tertiary basement is assumed to be 2.6km/s. © 1992, The Seismological Society of Japan, The Volcanological Society of Japan, The Geodetic Society of Japan. All rights reserved.