|In November it is 30 years ago the Nevada del Ruiz in Colombia erupted and caused massive lahars (mud and debris flows) which killed more than 20.000 people in the city of Armero|
More than 50 volcanoes in the United States have erupted one or more times in the past 200 years. The most volcanically active regions of the Nation are in Alaska, Hawaii, California, Oregon, and Washington. Volcanoes produce a wide variety of hazards that can kill people and destroy property. Large explosive eruptions can endanger people and property hundreds of miles away and even affect global climate. Some of the volcano hazards described below, such as landslides, can occur even when a volcano is not erupting.
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