FEASIBILITY OF LINEAR POLARIZATION MEASUREMENTS FOR DETECTING AND MEASURING SEISMIC BODY WAVES.

The application of P-polarization measurements at teleseismic distances is evaluated with test data synthesized by adding an observed teleseismic event to ambient seismic noise. Since the input SN ratio is controlled, signal distortion and the detection threshold of weak signals, as well as gains of strong signals, are evaluated from amplitude measurements. The results indicate that no increase in detectability is expected at teleseismic distances. Theoretical analysis of expected gain confirms the expected losses in P detection at epicentral distances greater than 40 deg but indicates substantial gains at lesser epicentral distances. Later phases such as SP and PP should be more detectable in the teleseismic range using polarization measurements. Shear phases such as S and PS, etc., are always expected to be more detectable on the radial component than with polarization measurements. Author