New research by a team of US and UK scientists into volcanoes has found that they function in a far more complex way than previously thought, making future eruptions even harder to predict.
The findings by scientists at the University of East Anglia (UEA) in the UK and Penn State University and the University of Arkansas in the US, will be published in the journal Science on Friday October 10.
The principal discovery is that rather than 'ballooning' at depth, as previously thought, the pressurised magma in fact recharges the volcano repeatedly, causing episodic eruptions at the surface.
The research was conducted on the Caribbean island of Montserrat, a UK territory on which the Soufrière Hills Volcano has been erupting since 1995. It has caused widespread damage to the island and its infrastructure, resulting in the displacement of so many people that the island's population has reduced from 13,000 to just 4,500. In 1997, avalanches of hot rocks, known as pyroclastic flows, destroyed the capital town of Plymouth and the island's airport. More than 20 people were killed.
The team of scientists and colleagues at the Montserrat Volcano Observatory measured the surface flux of lava through detailed topographic surveys of the lava dome and deposits. They also measured the response of the ground surface around the volcano using GPS (global positioning system) to assess the amount of inflation or deflation in response to magma movement. They have developed a physical model to reconcile these measurements and provide a picture of how magma moves from the mid-crust to the surface.
Richard Herd of the University of East Anglia said: "I worked on Montserrat for seven years and saw at first hand the terrible devastation inflicted by the Soufrière Hills Volcano.
"Our findings show volcanic eruptions to be even more complex than we had originally believed and illustrate the urgent need for further research into this and other volcanoes."
'Implications of Magma Transfer Between Multiple Reservoirs on Eruption Cycling' by Derek Elsworth, Joshua Taron and Barry Voight (all Penn State University), Richard Herd (University of East Anglia and Glen Mattioli (University of Arkansas) is published in Science on October 10.