Some Investigations of Shallow Earthquakes (II)

[摘要] This paper contains the following results: (1) The position of nodal-line and the distribution of amplitude of initial motion for some earthquakes were treated by means of the next relation: initial motion at the surface ∞P2(cosθ)/γThe path of seismic rays was considered in two cases assuming that the mechanism of earthquake is the “Nodal-cone type”. The one denied the exiteuce of the surface of discontinuity near the earth surface and the other assumed it. Comparing with the actual seismic observations, the author has ascertained that they are in good ag eement with the former case.(2) There appears the azimuthal distribution of maximum amplitudes in vertical component at the actual ea lhquakes of shallow origin and their greater part is in very good agreement with theoretical results of Rayleigh wave due to the dilatational wave issued from an internal source of multiple-type in a semi-infinite elastic body.

[学科分类] 大气科学