Volcanic Eruption: Frictional Heat Can Trigger Explosive Eruptions, Study Says
Researchers from the University of Liverpool have found that the temperature of magma may be more important than previously believed when it comes to causing explosive volcanic eruptions. Originally, scientists believed that gas bubbles generated by pressure had the biggest influence on eruptions.
The team, from Liverpool's School of Environmental Sciences, showed that magma heats up when it climbs volcanic conduits, which gives it the ability to melt its crystal cargo, forcing the formation of bubbles, according to a press release. The team also showed that heating actually caused more bubbles than decompression than they had previously believed.
The study took a combination of field observation, controlled lab experiments and interpreted monitored data to provide an argument to show how temperature is key for volcanic eruptions.
"A good analogy to this is peanut butter: when it is too cold and viscous, we plunge a knife into it and stir to warm it up and make it more runny," Yan Lavallée, the lead researcher, said. "With volcanoes, magma ascending in volcanic conduit also heats up and this helps them foam and erupt explosively."
Magma ascent and our understanding of it is vital to predicting volcanic disasters and eruptions. Our lack of knowledge about the signs of a volcanic eruption does not allow us to accurately predict these events.
"The fact that temperature may be more important than pressure in the generation of gas bubbles in ascending magmas is astonishing and requires immediate consideration from the scientific community," Lavallée said. "The fundamental nature of this thermal process will very likely find other important applications in earth sciences as well as in engineering in the years to come."
The team designed lab experiments to reproduce the volcanic eruption process, allowing them to study friction in volcanic rocks. They found that this friction causes a vast amount of heat between the rocks, melting them and creating foam.
Volcanic eruptions are often compared to uncorking champagne - a slow uncorking causes bubbling and foaming, while a quick uncorking results in the cork flying into the air and the wine splashes out. With volcanoes, eruptions can either result in lava flows or explosions. Scientists had believed that a decrease in pressure caused the "foaming," but their findings have shown that heating may be more important in controlling these eruptions.
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