Analysis of explosion generated surface waves in Africa, results from the discrimination experiment and summary of current research. Quarterly report, 1 January--31 March 1978

Abstract : Brief summaries of work currently underway or recently completed are given in four study topic areas: Source, Data Analysis, Surface Wave, and Body Wave. The remainder of the report presents research results not previously reported: (1) Discrimination Experiment--Digital short- and long-period body and surface wave data for Eurasian events recorded at a global network of stations are being provided for event discrimination. Efforts have focused on application of the VFM (Variable Frequency Magnitude) discriminant to the short period P waves at four stations; (2) Analytic Continuation of the Elastic Field from a Complex Source in a Halfspace. This section presents the mathematical development of a method for linking finite difference numerical source calculations in a halfspace with analytical techniques for propagating elastic waves in layered media; (3) Theoretical Computation of Lg--This discussion is concerned with the theoretical generation of Lg in a continental earth model. Synthetic seismograms are shown for several ranges and source depths, and (4) Analysis of Surface Waves from the French Test Site in the Sahara.