Montserrat, a small Caribbean Island southeast from Puerto Rico, made headline news in July 1995, when the country's dominant volcano, SoufriÃÂ¨re Hills, blew out steam and ash from its northwest crater. Eruptions accompanied by earthquakes continued ever since, featuring different stages of more or less activity. Villages in the southern parts of Montserrat, including the capital Plymouth, had to be relocated to the north of the island, where there is less danger of volcanic activity.
What caused the SoufriÃÂ¨re Hills Volcano to erupt?
The Caribbean island of Montserrat is situated on a destructive plate boundary. A plate boundary occurs when two of the plates that makes up the surface of the earth meet. Underneath Montserrat the Atlantic plate is slowly being forced under the Caribbean plate. This happens because the oceanic plate is denser than continental plate. Convection currents pull the dense Atlantic plate into the mantle where intense heat and friction cause the rock to melt.
This molten rock is lighter than the surrounding rock, forcing it to rise through cracks in the in the rock towards the earth's surface.
Molten rock or magma gathers under the volcano until the pressure is so great that it is forced up through a vent towards the surface of the earth. The SoufriÃÂ¨re Hills Volcano produces a thick sticky lava called andesite. The lava is so thick that it builds up at the top of the volcano in a dome until it becomes too heavy and the dome collapses. When the dome collapses hot rocks, gases and ash are released from the volcano causing the following hazards. Pyroclastic flows are extremely fast-moving flows of lava, hot rocks and gas that flow down the side of the volcano. Pyroclastic Surges are fast-moving clouds of hot ash that travel with the pyroclastic flow. Tiny...