The stone can tell a lot
Minerals emitted by the eruption of volcanoes, can tell a lot. Even predict when there will be new eruption.
The composition and structure of the rocks, which are formed during the cooling of molten magma is determined by the conditions in which they were inside the volcano. However, to establish the composition and structure of what really happened in the bowels of the volcano is not very easy. In the depths of a small mineral crystals no larger than 50-100 microns, which float in the hot magma. Many crystals are formed of concentric layers than that resemble tree rings. In these layers and reflects all the events taking place in the crystal.
For example, each new release of magma from the depths of the volcano there is a movement of certain elements that make up the chip from the middle to the edges of the layers, thus forming a new outer layer. Often a weak eruption takes place before a larger scale, and these crystals can be thrown to the surface where they solidify. If they do a thorough analysis, it is possible to speculate what might be inside the volcano.
The scientists decided to find out whether the crystals can predict future eruptions. For the study, they took samples of orthopyroxene obtained from the slopes of Mount St. Helens in the north-western United States. The most powerful of its eruption occurred in 1980, while smaller place until 1986.
In total, scientists have identified 98 individual crystals collected during this period, and compared them with those of an eruption, gas emissions and some other events. Thus, they found that the crystal starts to grow at about a year before the eruption, and reaches its maximum size directly in front of him. That is, crystals with magnesium-rich outer layers and saturated iron core, they say that is not far off a new eruption.
On the other hand, crystals are formed during cooling of the medium in which they are located. Then they have to rush to the later, the weak eruption.
Using these data, we can determine whether the expected new powerful eruption, or vice versa, the magma inside the volcano cools down and gets rid of excess gas, while the remaining occur, weakening the eruption.
