Background:Steep-sided, conical Opala stratovolcano is one of the most dramatic volcanoes of southern Kamchatka. The 2475-m-high volcano was constructed during the late-Pleistocene to Holocene at the northern end of the 12 x 14 km, 40,000-year-old Opala caldera. The volcano has produced andesitic-dacitic lavas and tephras through most of the Holocene. The latest major explosive eruption formed the prominent Barany Amphitheater on the SE flank about 1500 years ago, producing a voluminous 9-10 cu km regional tephra marker layer of rhyolitic composition. The 2 x 2.5 km crater is filled by a lava dome 1 km wide. Mild explosive eruptions have been reported from summit and flank vents at Opala in historical time, although no associated tephra deposits have been found. Recent tephrochronological work has revealed evidence, however, for a large explosive eruption from the summit crater about 300 years ago.
Smithsonian / GVP volcano information