Study of Selected Events in the Baikal Rift Zone in a Seismic Discrimination Context

Analysis of Selected Seismic Events from Asia in a Seismic Discrimination Context

“…Again, small magnitudes (mb < 5.3) preclude determination of source mechanisms for these events. However, the predominance of negative first motions at teleseismic distances suggests that these events are normal faults on steeply dipping planes, which agrees with known focal mechanisms for this region (Sobel et al, 1977b). Note that some LASA and NORSAR first motions are positive, indicating the vagaries of presumed first-motion directions for small-magnitude events.…”

“…and faults bordering a system of grabens are clearly observed on satellite photographs of the area (Sobel et al, 1977b). With normal faulting the nodal plane of the P radiation pattern is downward, giving positive and negative first motions to teleseismic signals.…”

“…Sobel and von Seggern, 1976;Sobel et al, 1977aSobel et al, , 1977bSobel et al, , and 1977c, to identify the major source and path effects which impact upon discrimination of Asian events and to assess likelihood of correct event identification in these regions. However, the problem of regional effects can be circumvented by limiting the computation of a discriminant function for earthquakes and explosions to events within a geophysically distinct region.…”