Statistical Evaluation of the Focal Mechanism Solutions for Thirty-Six 1962 Earthquakes

摘要

The S Wave Project for Focal Mechanism Studies recently completed a study of thirty-six of the larger magnitude earthquakes that occurred during 1962. Welldetermined solutions employing a double-couple model were obtained for twenty-three of these shocks and tentative solutions for the remaining thirteen. This study attempts to specify the agreement between the observed data (direction of first motion of the P wave and polarization angle of the S wave) and the theoretical values of these data as implied by the focal mechanism solutions obtained. To describe the agreement between observed and theoretical P wave patterns, a P Wave Agreement Factor (PAF) is defined and applied to each of the well-determined focal mechanism solutions. The PAF, with a range of zero to four, attempts to specify both the adequacy and consistency of the P wave data by accounting for the number of quadrants of data and by weighting each data point with respect to its distance from nodal lines.