The Effects of Source on the Generation of Short Period Surface Waves

短週期表面波生成過程之震源效應

葉永田(Yeong Tein Yeh) ； 鐘仁光(Jen-Kuang Chung)

《Terrestrial, Atmospheric and Oceanic Sciences》 4卷4期 (1993/12) Pp. 351-366

並列摘要

Short-period surface waves can usually be observed on strong motion records. Theoretical seismograms provide a useful tool for the prediction and interpretation of differences in the surface wave excitation of various earthquakes. The complex polarization filter followed by Vidale (1986) is used in this paper. The influence of source parameters (source depth, source type and orientation) on the excitation of Rayleigh waves for the elastic halfspace and a single layered half-space model is discussed in detail.
Results show that the epicentral distance beyond which the fundamental mode Rayleigh waves can be generated is around 3 to 5 times of the source depth for the point dislocation source in the half-space model. These critical distances are a little longer than those for the finite length sources. The orientation parameter is not generally of significance. When a flat low-velocity layer is overlying on the top of the half-space, the computations suggest that the complex waveforms are observed and about 10 km of the critical distance obtained is not changed for all kinds of sources used in this study. Moreover, the most important quantity for identifying the Rayleigh wave, namely the ellipticity, is estimated to be in the range of 0.6 to 0.7, except with a layer over half-space model.