ABSTRACT

In January, 1959, two series of small earthquakes originated in southern Owens Valley. The first and largest of these, of magnitude 4.7, originated on January 5, 12:36:02.9 GCT, near 36° 09′ N, 118° 03′ W, near Haiwee. This and other shocks of the series were well recorded by standard and strong-motion instruments at Haiwee, showing the characteristic false S - P of about one second. The timing is good, and demonstrates that no change of supposed epicenter, depth, or velocities can reasonably account for the second phase as S. Other shocks were located at 36° 07′ N, 118° 03′ W, which probably represents the terminus of faulting in the first shocks.

A shock of magnitude 3.2 occurred on January 7, at 00:20:40.2 GCT near 35° 46′ N, 117° 35′ W, near China Lake. This was followed by numerous others from the same source, mostly showing a false S, and recorded by the Benioff instrument at China Lake down to very small magnitudes. However, shocks of this group of magnitude 0.7-0.8 were more numerous than those of magnitudes 0.0-0.6.

Initial compressions and dilatations in both groups of shocks were consistent, especially at the nearer stations, but lead to no simple fault-plane solutions.

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