Yantarni Volcano is an andesitic stratovolcano in the U.S. state of Alaska. It is on the Alaska Peninsula, in the Aleutian Range, between Mount Aniakchak and Mount Chiginagak volcanoes. The volcano was not discovered until 1979 due to its remote location, lack of documented historic activity, and its rather modest summit elevation. The mountain was named after nearby Yantarni Bay, which in turn was named by Russian explorers after the abundance of yantar in the area. Geology The current cycle of eruptive activity began in middle Pleistocene time with extrusion of andesitic lava flows, perhaps from multiple vents. By the late Pleistocene, central-vent volcanism had initiated construction of a small stratovolcano. 800 BCE ± 500 years eruption The cone was breached sometime in the late Holocene, between 2 and 3.5 ka, during the only Holocene event. The eruption was similar to that of Mount St. Helens. and was followed by the emplacement of 1 cu km of pyroclastic flows related to growth of the summit lava dome. It had a Volcanic Explosivity Index of 5 Notes Sources Volcanoes of the Alaska Peninsula and Aleutian Islands-Selected Photographs Volcanoes of Lake and Peninsula Borough, Alaska Mountains of Lake and Peninsula Borough, Alaska Stratovolcanoes of the United States Mountains of Alaska Volcanoes of Alaska VEI-5 volcanoes Aleutian Range Pleistocene stratovolcanoes Holocene stratovolcanoes