窪みのある大陸性地殻構造におけるラブ波伝播

抄録

Love wave propagation for a continental crustal model with a dent is simulated by the two-dimensional finite difference method. Snapshots of displacement clearly show that complex phase and amplitude distributions on the free surface, as well as near the boundaries of the Moho discontinuity, are produced by the interference between incident and scattered waves. Snapshots of scattered waves show that a part of the energy of the incident wave generates secondary waves due to the scattering at irregular Moho discontinuity. The energy of scattered waves is strongest at the edge of a dent in wave's outgoing direction. Defining the propagation from thinner to thicker crust as a downdip propagation and the reverse case as an updip propagation, scattering characteristics of Love waves at a dent indicate that short- and long-period SH waves are radiated in the downdip and updip propagations, respectively. The body waves, which make a constructive interference with surface waves, anomalously raise transmission coefficients of Love waves for short- and long-periods at the edges of a dent in wave's incoming and outgoing directions, respectively.