University of Pittsburgh
Among the world’s largest and most dangerous: volcanic dome-collapse derived Block and Ash flows on Shiveluch volcano, Kamchatka.
Volcanic domes are large plugs of solid lava that are extruded at a volcanic vent, and when they collapse they can destroy everything in their path as a disastrous rapidly moving mass of hot rock, ash, and gas. Shiveluch volcano in Kamchatka, Russia, is one of the world’s most active dome-producing volcanoes, and produces some of the largest historical block and ash flows, globally. Linking the deposit distribution and runout to the size, location, and temperature profiles of the area of dome collapse using a range of satellite data provides a basis for determining the distribution and extent of future hazards at similar volcanoes. Eight large dome-collapse block and ash flow eruptions and their deposits were investigated using satellite (ASTER and high-resolution Digital Globe sensors) and field data. The largest deposits have runout distances up to 18 km from the dome summit and cover areas up to 24 km2, depositing large boulders (> 11 m maximum diameter) to distances greater than 11 km. Over the 16 years (and counting) of this current eruption phase there has been no trend in size or runout distances of the flows, even though the dome continues to increase in size. The majority of the dome collapse events were preceded by a thermal hotspot in the location of the collapse, although the hot spot area does not correlate with the size of the collapse event. Field and satellite data show evidence of pulsatory collapses, where the dome collapsed in multiple phases over the hours of the eruptions to produce one large deposit. Understanding these prolonged eruptive episodes and the extreme end of the deposit size spectrum is important for volcanic hazard analyses and mitigation by giving maximum dimensions for areas affected by this eruption type.