The latest major explosive eruption formed the prominent Barany Amphitheater on the SE flank about 1500 years ago. The 2 x 2.5 km summit crater contains a lava dome 1 km wide. Mild explosive eruptions have been reported from summit and flank vents at Opala in historical time. Recent tephrochronological work has revealed evidence for a large explosive eruption from the summit crater about 300 years ago.
Melekestsev, I. V.; Felitsyn, S. B.; Kirianov, V. Yu. (1991). "Opala volcano eruption. A.D., 500 – the largest explosive eruption on Kamchatka in our era". Volcanology and Seismology13: 21–36.Cite uses deprecated parameters (help)