#Craters are common at the #summits of stratovolcanoes—aka composite cones—which are tall, conical #volcanoes made of layers of #lava, #ash, cinders, blocks, and #bombs like Vent Mountain shown here. Breaks in the #crater wall or other openings on the #volcano allow lava through. Vent #Mountain lies within the Aniakchak Caldera, a six-mile-wide, 2,000 foot-deep #caldera on the #Alaska Peninsula that formed when an #explosion caused the collapse of a 7,000-foot mountain and left behind a massive bowl of ash. #photooftheday #science #earth #photography #sciencephotos #aerial #birdseye