Global Volcanism Program | Image GVP-01645
Steam rises from a pyroclastic flow deposit on the NW flank of Ulawun in February 1970. Rainforest trees were blown down facing away from the volcano by a high-velocity pyroclastic surge at the margins of the 22 January pyroclastic flow, which traveled 5 km from the summit. Pyroclastic flow velocities on the upper part of the volcano were estimated to exceed 100 km/hour.
Photo by Robert Citron, 1970 (Smithsonian Institution; courtesy of William Melson)