Icelandic volcanoes help scientists understand potential effects of eruptions

Washington, July 15 : Scientists have mapped an elaborate maze of magma chambers that lie beneath Iceland's volcanoes, which could one day help in better understanding of how earthquakes and volcanic eruptions occur in Iceland and elsewhere in the world.

According to Daniel Kelley, doctoral student in earth sciences at Ohio State University, knowing where magma chambers are located is a key first step to understanding the chemical composition of the molten rock that is flowing within them - and of the gases that are released when a volcano erupts.

Previous eruptions in Iceland and elsewhere have released gas into the atmosphere that had global affects.

"One of the reasons we're trying to understand these volcanoes is to determine exactly what the chances are of a large eruption there," said Michael Barton, professor of earth sciences at Ohio State University.

"We know that a large eruption in Iceland would not only have devastating local effects, but potential global effects as well - by affecting the climate," he added.

This new study was based on the analyses of basaltic glasses - volcanic rocks created when magma from deep within the Earth is cooled very quickly at the surface and becomes glass-like.

The researchers traced the origin of basaltic glass rocks gathered from the surface of Iceland to magma chambers under 28 different volcanoes, by analyzing the composition of the rocks and calculating the pressures at which the glasses were formed.

Rather than using conventional methods, Kelley and Barton focused on a more unusual way to study Iceland. "By analyzing the glass, you have something that directly represents the liquid magma beneath the surface and gives you the exact location of the magma chamber," said Kelley.

This new research strongly supports the idea that the middle and lower layers are actually hotter than ever imagined, up to 400 degrees Celsius higher at the base of the crust.

At the base of the crust beneath every volcano, researchers also found complex groupings of magma chambers.

Magma is constantly flowing through the chambers or injected into cracks in the crust, resulting in increased volcanic activity.

"Over thousands of years, that increased volcanic activity has created a lot of basaltic glass, giving scientists clues at how magma chambers have changed over time and where eruptions have taken place in the past," said Kelley.

Knowing the sizes and locations of magma chambers past and present, scientists can better understand the events that happen shortly before and after a volcanic eruption. There's a lot of magma moving inside reservoirs underneath volcanoes as they fill, the crust around them becomes deformed and that tends to generate the earthquakes," said Barton."And so, one of the ways you are able to predict an eruption is by looking at the seismic data," he added.

ANI