The stress field rotations obtained from focal mechanism solutions were recorded during the swarms of volcano-tectonic earthquakes associated with the 1975 Tolbachik fussure eruption in Kamchatka , the 1992 Crater Peak eruption in Alaska and the 2004–05 Mount St. Helens eruption
During the 1975 Tolbachik swarm, this rotation was observed just after two Mw 4.9 earthquakes had occurred on July 2 simultaneously with the disappearance of HSD earthquakes (see Fig. 9.21). It continued up to the beginning of the eruption on July 6.