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Landslide and Rockfall Hazards at Crater Lake

Landslides or rock falls could be triggered within Crater Lake caldera by earthquakes or by renewed volcanic activity. Failure of part of the caldera wall could cause a rapidly moving material to enter the lake, which may produce one or more large waves that could travel rapidly across Crater Lake and impact its shore. Such an event would be particularly hazardous to National Park visitors and employees as well as researchers who spend time on the shores of the lake or in boats on its surface. Tours and research trips are taken to Wizard Island and around the lake, and there are structures used for boat maintenance and to house the boats during the winter. Large tsunami-sized waves could potentially cause loss of lives and infrastructure—particularly from an unanticipated landslide. 

Crater Lake, Chaski Bay. Talus slope sits on flat top of massive sl...
Talus slope sits on flat top of massive slide block that fell from upper wall, debris avalanche deposit on caldera floor. Future similar event would disrupt lake surface. (Credit: Bacon, Charles. Public domain.)