Type: Composite volcano with lava domes

The 10,000 or so residents of this small Lesser Antilles island have had their lives turned upside down by an unsettled volcano.

Underneath Montserrat, the North and South American plates push beneath the Caribbean plate in a subduction zone. From this tectonic activity rose Soufriere Hills, a stratovolcano on the southern end of the island.

The volcano had been quiet for nearly 400 years until 1995, when it burbled to life and sent islanders scurrying.

A series of eruptions began with occasional gray clouds of ash and steam. Then came pyroclastic flows—destructive mixtures of extremely hot volcanic fragments and gases that sweep along close to the ground. The flows swept down the volcano's eastern side and turned a green valley into a brown moonscape.

In September 1996, part of the volcano's dome collapsed, sending rocks shooting out of its crater for nearly an hour. The stony debris pelted nearby residents.

The government, fearing casualties or deaths, evacuated the southern end of the island, prohibiting anyone from inhabiting homes or businesses there. Evacuees fled to the north, jamming churches, community centers, and other makeshift shelters. Eventually more than half the population left the island, many taking advantage of free aid from Britain.

Scientists aren't sure when the volcano will quiet down, and it continues to throw ash and stone. In 1997, an eruption killed 19 people and buried the evacuated capital, Plymouth, which lies just 3 miles (4.8 kilometers) west of the volcano.