Some 1951 Earthquake Mechanisms based on P and PKP Data

I. Presentation of solutions T h e methods used here have been described in an earlier paper in this periodical (Ritsema 1960). The greater part of the data on which the solutions are based is taken from the International Seismological Summary. Additional data have been supplied by the respective seismic stations in reply to questionnaires. The co-operation of the Directors of these stations is gratefully acknowledged. I n Table I the data not reported in the I.S.S. are given. In Table 2 the solutions reached have been summarized. It is impossible to state which of the two nodal planes acted as fault plane because of the fact that only longitudinal waves have been used. Only one of the two possible solutions is given in the table. The other solution is found by interchanging the Aand C-axes and by changing the dextral (respectively sinistral) part of the fault motion into a sinistral (respectively dextral) part. T o give an insight into the reliability of the solutions the numbers of consistent and of inconsistent data are given in the last column of Table 2.