The time of the volcanic eruption and its magnitude can be predicted by how much the height of its vents and adjacent surroundings has changed, say geologists in an article published in the journal Science Advances.
“Watching the Kilauea volcano, we wanted to understand whether changes in the speed of seismic waves through it indicate how pressure builds up inside the volcano at a time when it” swells “before the eruption begins. Understanding whether this connection exists or not , Is critical to the prediction of eruptions, “says Clare Donaldson of Cambridge University (UK).
Under each volcano there is a magma chamber – a reservoir of porous rocks that can absorb large amounts of liquid magma. Before the eruption, this chamber overflows, which leads to its “inflation” and the rise of the altitude in the vicinity of the volcano. By how much the camera has “blown up”, scientists can estimate the volume of magma contained in it and give an estimate of the strength of the eruption and the likelihood of its occurrence.
The process of filling this chamber, as scientists explain, usually takes place “jerks”, and not at a constant rate. As a result, the pressure inside the magma chamber changes dramatically, and these changes give rise to relatively weak and long-period seismic waves moving toward the surface. The man does not feel these tremors, but the instruments of seismologists fix them for each active volcano.
Similar measurements, according to Donaldson, can not always be carried out near the volcano’s surroundings, and they can not be “seen” using satellites and other space and air observation systems. On the other hand, the effects of the “swelling” of the magmatic chamber will be clearly visible for both climatic and navigation probes.
Donaldson and her colleagues found that such measurements would be sufficient to predict when the volcano erupted, watching the activity of the Kilauea volcano for the past four years.
As the scientists say, the current eruption of the “main” volcano of the Hawaiian Islands began more than 30 years ago, in 1983, and since then it has never faded, periodically raising or lowering the level of activity. Such a troubled character Kilauea is only a plus for geologists who are virtually continuously watching the changes in the state of its magmatic chamber all this time.
Donaldson and her colleagues collected data from two seismic sensors, which they installed on two opposite slopes of Kilauea to obtain some kind of “photos” of the magma chamber.
Analyzing these changes, geologists noticed that the changes in the nature of the motion of seismic waves through the “heart” of the volcano were accompanied by well-marked changes in the topography of the area. In other words, all the changes inside the volcano could be calculated by how much its height, the slope angle, and also the height of the surrounding regions of the terrain changed, a few days before the beginning of the new eruptions.
This, in turn, opens the way for predicting the time of volcanic eruptions and where they will occur, using relatively simple measurement and observation techniques, scientists conclude.