The volcano
Volcanic activity in the West Indies is the result of the subduction of the South American plate under the Caribbean plate.
The type Pelean was defined in 1902 and apply to the Mount Pelee (Martinique, French West Indies).
This is a special case of an explosive eruption . The lava is a pasty one, because really rich in silica. It cannot flow out of the crater and piles up there , often forming a dome spiked with needles. When the gas pressure beneath the lava plug that fills the crater becomes greater than the resistance of the plug, a pyroclastic flow burst from a tear at the base of the dome. The explosion , consisting of lava and hot gases and boulders of all sizes escaping at speeds of several hundred kilometers per hour, is very destructive , especially since it is preceded by a shock wave ; these powerful destructive flows are called pyroclastic flows . In 1902, in Martinique, pyroclastic flows instantly destroyed the town of Saint- Pierre and its 30,000 inhabitants.
The mass of lava that clogs the chimney is expelled slowly between two explosions and forms a pelean dome (eg . The Puy de Dome in France).
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