U.S. ranks high with active volcanoes and eruption-warning capability

Veniaminof Volcano, Alaska, erupting lava from the top of a cone located in the western part of its 8 x 11 km- (5 x 7 mi-) wide caldera on July 16, about a month after the eruption started. The lava is flowing down a narrow channel of the cone, beneath an approximately 60-m- (200-ft-) thick cover of snow and ice in the caldera. The cone rises about 300 m (1,000 ft) above the surface of the ice. An enormous eruption about 3,700 years ago expelled an estimated 100 cubic kilometers (24 cubic miles) of magma—about 100 times the size of the 1980 eruption of Mount St. Helens—resulting in the collapse of the volcano to form the caldera. Veniaminof, which has sustained more than 20 eruptions since 1800, is one of Alaska's most active volcanoes. Photograph by the Alaska Volcano Observatory, U.S. Geological Survey.