Mount Unzen is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island.
Mt. Unzen, showing extensive pyroclastic flow and lahar deposits
In the distance, Mt. Unzen's Fugen-dake (left) and Heisei-Shinzan peaks, the latter a lava dome that emerged during the 1990–1995 eruption, seen from Nita Pass in November 2005
Spaceborne radar image of Unzen, taken from Space Shuttle, April 15, 1994
House destroyed and partially buried by lahars in the Mizunashi River valley, 1994
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica, with lesser amounts of less viscous mafic magma. Extensive felsic lava flows are uncommon, but have traveled as far as 15 km (9 mi).
Mount Rainier, a 4,392 m (14,411 ft) stratovolcano, the highest point in the US state of Washington
Exposed internal structure of alternating layers of lava and pyroclastic rock in the eroded Broken Top stratovolcano in Oregon
Mount Etna on the island of Sicily, in southern Italy
Snow-like blanket of Mount Pinatubo's ashfall deposits in a parking lot on Clark Air Base (June 15, 1991)