1971 年 24 巻 4 号 p. 318-334
The distributions of stresses around an elliptical fault plane in an infinite homogeneous elastic medium have been calculated. There are some regions where shearing stresses are not decreased but significantly increased. It indicates that a shear fault has a strong tendency to propagate itself and this corresponds to the occurrence of aftershocks. From the change of each components of stresses it is expected that large aftershocks which occur on and around the x1 and x2-axis have similar mechanism to that of a main shock, and aftershocks in other regions have different mechanisms.
Dynamic displacements in the near field around a propagating fault have been calculated for the various types of faulting. The different characteristics of the fault are reflected in the wave forms related to the far field terms. There are some regions where the polarities of initial dynamic displacements are opposite to those of static displacements. Some of the results given by HASKELL (1969) have been checked under the same conditions as his calculations and essentially different results have been obtained.