Dateline: August, 1996

Here are the facts and a review of what is known so far.

• On the island of Montserrat, the Soufriere Hills volcano is active. By early April 1996, increasing activity foced government authorities to evacuate the capital city of Plymouth.
• Scientists are studying volcanic data to predict eruptions.
• The volcano on Montserrat is a stratovolcano, or composite volcano made up of layers of tephra, ash, and lava flows, much like Mt. Pinatubo in the Philippines.
• Studying these facts may help to understand the Montserrat situation more fully:
  • The Earth has layers: the lithosphere; the hot, convecting mantle; and the dense iron core.
  • Huge tectonic plates in the lithosphere constantly move at rates of centimeters per year in response to changes in the semi-liquid mantle. Major geological events, such as earthquakes, volcanic eruptions, and mountain building, result from these plate motions.
  • Landforms are the result of a combination of constructive and destructive forces. Constructive forces include deformation of the Earth’s crust and volcanic eruptions. Destructive forces include weathering and erosion.
  • Some changes are part of the "rock cycle." Volcanoes contribute to the rock cycle by bringing molten rocks to the surface to create new landforms. Over the ages, these landforms weather and erode, creating sediments that may be buried, then compacted, heated, remelted and recrystallized to form new rock. Eventually, those new rocks may be brought to the surface again and the cycle begins anew.
• Dangers on the island of Montserrat are many. The volcano may create lava flows, pyroclastic flows, and landslides. Lahars may occur after rainstorms. Falling tephra may land on people or buildings causing harm.
• Predicting an eruption is not an exact science. Scientists study patterns of past eruptions and apply the lessons they learn to real-time data.
• To understand volcanic activity on Montserrat one should examine changes in land deformation, ash clouds, and volcanic tremor and rockfall events (VT and RF).