The fundamental-mode interstation group and phase velocities andattenuation coefficients of Rayleigh waves along four paths across the Philippine Sea are determined to have periods of between 20 and 110 secondsby the two-station method. The values of group and phase velocities arequite consistent with the results of previous studies using the single-stationmethod. Group and phase velocities vary significantly with different wavepaths at periods of less than 50 seconds, but for longer periods, the phasevelocities are quite close. The inversion results show that the thickness ofthe lithosphere is about 60 km in the Philippine Sea, except in the area ofthe eastern volcanic islands where a slightly thinner lithosphere (about 50km) is deduced. The attenuation coefficients observed in the Philippine Seaare higher than the values obtained in the Pacific. This result simply reflects that the Philippine Sea plate is younger than that of the Pacific. Lateral variation in attenuation coefficient is not as clear as it is in velocitybecause of its large variance. However, the vertical distribution of Qβ-1 isquite similar to that for the shear velocity model.
關聯:
Terrestrial, Atmospheric and Oceanic Sciences 11:2 民89.06 頁515-524
