Indonesia has the deadliest volcanoes on earth. Despite the fact that Indonesia has about 130 active volcanoes, little is known about why the volcanic eruptions in Indonesia are so explosive causing a huge death toll. Now, in a recent study published in Nature Communications, scientists claim that they have found clues to why the eruptions in Indonesia are so explosive. According to them, the explosiveness of a volcano depends upon the nature and compositions of its magma, a hot, dense and fluid or semi-fluid material in the mantle, just below the earth’s crust.
Magma can also be called molten rock because when it comes out of the volcanoes becoming lava, it forms igneous rocks after it cools down. However, magma is not found everywhere below the earth surface, but their composition largely differs across the geological regions where they are found. When magma gets a chance to pierce the earth’s surface, it erupts through volcanoes.
To study the properties of the magma, the international team of scientists studied the lava recently ejected from four Indonesian volcanoes. Scientists used ultramodern mass spectrometers to examine the mineral crystals in the lava to study their composition.
In Indonesia, this fracture in the earth’s crust is caused by the process of subduction, a process in which continental plates collide with each other and one plate slides beneath the other descending into the mantle. The descent causes heating up of the plate and release of the water contained by the plate leading to the melting of the surrounding rock. “When the magma reacts with, for instance, the limestone that’s found in central Java right under the volcano, it becomes full to bursting point with carbon dioxide and water, and the eruptions get more explosive,” says Valentin Troll, one of the authors of the study.