Resolving Focal Mechanism Solution’s Ambiguity through Perturbation Applied to Mindoro Earthquakes

The problem of the present study is to determine which of the two planes of a Focal Mechanism Solution (FMS) is the fault plane. In order to resolve this problem of ambiguity in focal mechanisms, we use the method of perturbation of the fault parameters such as azimuth and dip of the x and y planes. As an example of the application of this method, FMSs of Mindoro earthquake events (1968-1994) were obtained from the Bulletin of the International Seismological Center (ISC). An algorithm that uses perturbation has been developed to discriminate between the two planes. For events without Harvard CMT solutions, its FMS were determined from data
sets of first P-wave onsets.