(ORDO NEWS) — Acoustic waves propagating from a lava lake on a volcano make it possible to determine the temperature and composition of the lava hidden in the depths and to notice an imminent eruption in time.
When a large piece of rock falls into a lake of molten lava, the vibrations it creates propagate through the thickness of the entire volcano.
The characteristics of these waves make it possible to estimate the temperature and composition of the magma hidden at depth, and to predict in advance the active and dangerous phase of the eruption.
This work was done by a team of American geologists based on data collected in recent years in Hawaii.
In 2007-2008, one of the craters on the top of the Hawaiian Kilauea volcano began to slowly fill with molten lava.
The eruption developed gradually, and the lava lake at the top of Kilauea became a popular tourist attraction.
However, unhurried accumulation of magma continued at depth, and ten years later the volcano experienced a series of earthquakes that caused the collapse of a significant part of the caldera, accompanied by ash ejections and lava flows .
All these years, geologists have been tracking the behavior of Kilauea with a variety of seismographs. Sensitive instruments registered the vibrations created by the debris falling from the edge of the crater into the hot lake.
These waves also penetrate through the magma lying under the lava lake. The amplitude, height and duration of these “songs” depend on the composition, density and temperature of the magma, its saturation with various gases.
And the data collected on the Hawaiian volcano made it possible to obtain a model that describes this connection.
This work was done by a team of volcanologists led by Leif Karlstrom from the University of Oregon (USA).
Comparing the predictions of their model with real data, scientists have learned to determine the characteristics of the volcanic magma lying at depth – primarily its temperature and the composition of the contained gas bubbles.
Until now, such information could be obtained only after the beginning of the active phase of the eruption, when samples of ejected magma fell into the hands of scientists.
According to the authors of the study, their model will be useful for tracking and predicting eruptions not only in Kilauea, but also in many other active volcanoes in the world.
While they refine and expand their calculations, they supplement it with machine learning models for more accurate predictions.
It is a pity that not all volcanoes accumulate such a convenient lava lake, so the method is unlikely to become universal. But, fortunately, geologists are developing other methods of prediction, including using satellite data and GPS .
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