Reliability of focal mechanism determination

The fault plane solution determined by means of a computer algorithm, correlating the radiation pattern with the distribution of observations, was investigated from the point of view of its reliability. The maximum of the correlation function R corresponds to the optimum solution found by the computer. If the families of nodal lines fitting the decreased correlation function R —dR retain the character of the optimum solution even whendR increases, we assume that the solution has been determined with a sufficient accuracy.