Automated Magnitude Measures, Earthquake Source Modeling, VFM Discriminant Testing and Summary of Current Research.
Quarterly technical rept. 1 Oct-31 Dec 78
SYSTEMS SCIENCE AND SOFTWARE LA JOLLA CA
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Brief summaries of work currently underway or completed during the period from 1 October to 31 December 1978 are given in seven sections Source Calculations, Discrimination, Yield Determination, Small-Scale Experiments, Selected Geological Studies, Magnitude-Yield Improvements and Ground Motion Analysis. The remainder of the report is devoted to presentation of results not previously reported from three research projects. The first is concerned with the development and testing of an automated spectral body wave magnitude. The second detailed discussion is entitled, Three-Dimensional Earthquake Modeling. Results from two finite difference simulations of earthquake faulting performed on the ILLIAC computer are summarized. In one case, the material was elastic, and in the second, plastic yielding was allowed near the fault plane. The third detailed discussion is entitled, Discrimination Experiment. Two modifications to the MARS program use for discrimination are described. One is an algorithm for correcting for the effects of seismic noise. The second is an algorithm for averaging weighted estimates to obtain the high and low frequency magnitudes used to classify events.