Source mechanisms of two major destructive earthquakes which occurred at the Bihar-Nepal border and in the Quetta region on January 15, 1934 and May 30, 1935, respectively, are determined using the P-wave first motions, S-wave polarization angles, and surface-wave spectral data. The high stress drop and apparent stress associated with these events suggest that high tectonic stresses are prevailing in these regions. A major part of the stresses accumulated before the occurrence of the two earthquakes had been released through the main shock. An investigation of temporal and spatial variation of regional seismicity reveals possible existence of seismic gaps before the occurrence of these two major events.
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