How Volcanoes Work

 Image Described in Caption Mt. Unzen lava dome, Japan -- The Mt. Unzen lava dome looms over the Mizunashi River Valley. Growth of the lava dome from 1991 to 1995 was associated with hundreds of nuée ardentes. The current valley floor is covred in loose block-and-ash deposits of these pyroclastic flows. The flows destroyed hundreds of homes and covered what was once lush farmland. Courtesy of USGS.