Phase equalization was carried out for R waves in order to obtain information on source mechanisms of four earthquakes, the Kurile earthquake of 1963, its largest aftershock, the Rat Island earthquake of 1965, and the Tokachi-oki earthquake of 1968. The initial phase was computed using the corresponding complete great-circle phase velocity, so that influences of the lateral heterogeneity of the earth's structure were considerable reduced. The fault length of the Kurile earthquake was determined from the initial phase radiation pattern on the basis of a simple propagating fault model. There is no trade-off in this method between the fault length and the rupture velocity. Such a trade-off is inherent to the conventional directivity method. A fault length of 250 km was obtained, which was found to be nearly equal to the length of the aftershock area. We have introduced a dynamic fault parameter 'source time' that can be determined from the phase measurement using the complete great-circle phase velocity rather than the average phase velocity of the individual multiple R waves. This quantity corresponds to the rise time of the source time function of an equivalent point source. Source times of 97, 62, 174, and 115 s were obtained for the above four earthquakes.