New Volcanic Revelations May Help Predict When Eruptions Will Occur
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Gerard LeBlond for redorbit.com – Your Universe Online
The process of frictional melting determines how the volcano will erupt. The speed of the lava rise and how much friction it creates is determined by this process. Within the lava dome the magma and rocks melt as they rub together by the intense heat. This creates a method called ‘stick-slip’ when the magma adheres to the rocks and stops moving upward until pressure builds — when enough pressure builds up, the magma moves upward again. This process continues until the magma reaches the mouth of the volcano in an eruption.
By studying the stick-slip process, a research team, led by University of Liverpool volcanologist Dr. Jackie Kebdrick, has conducted experiments that could help predict eruptions.
“Seismologists have long known that frictional melting takes place when large tectonic earthquakes occur. It is also thought that the stick-slip process that frictional melting generates is concurrent to ‘seismic drumbeats’ which are the regular, rhythmic small earthquakes which have been recently found to accompany large volcanic eruptions. Using friction experiments we have shown that the extent of frictional melting depends on the composition of the rock and magma, which determines how fast or slow the magma travels to the surface during the eruption,” Dr. Kendrick stated.
The researchers analyzed lava collected from Mount St. Helens in the United States and the Soufriere Hills volcano in Montserrat. Remnants of pseudotachylyte, which is a cooled friction melt, were found. The study also revealed the process takes place in the conduit leading to the top of the volcano before its eruption.
“The closer we get to understanding the way magma behaves, the closer we will get to the ultimate goal: predicting volcanic activity when unrest begins. Whilst we can reasonably predict when a volcanic eruption is about to happen, this new knowledge will help us to predict how the eruption will behave. With a rapidly growing population inhabiting the flanks of active volcanoes, understanding the behaviour of lava domes becomes an increasing challenge for volcanologists,” Kendrick concluded.