earth scientists have a hard time with the prediction of the consequences of severe natural events, the earth’s interior come from. So the prediction of earthquakes, in spite of the intensive research in the past decades, is still not possible. Also of impending volcanic eruptions can usually only be warned to be insufficient. The reason for this is that the physical and chemical processes in the earth that lead to earthquakes and volcanic eruptions, are extremely complex and, therefore, not with simple formulas to describe. In spite of all obstacles succeeded Italian Geoscientists to develop an automatic system for volcanic eruptions forecast. For eight years they have tested it on mount Etna in Sicily, and could almost say, 97 percent of all explosive eruptions in this period, as well as reliably predict.
unlike the earthquake, it manages the geoscientists, at least occasionally, eruptions of volcanoes to predict. These warnings are mostly based on the Monitoring of earthquake activity below a volcano. According to the movement of the liquid magma within the earth the herd of dozens of small volcanic Hiking of the earthquake. This herd reached the vicinity of the surface of the earth, is often a magma eruption directly. Such seismic activities, however, are not a reliable indicator. It always comes back before that volcano eruptions by earthquakes or other physically measurable parameters to announce. Earthquake foci can also wander in the direction of the earth’s surface, without that it comes to a volcanic eruption.
Traitorous low-frequency signals
The research group led by Maurizio Ripepe, from the University of Florence has embarked on in the search for a reliable early-warning possibility of a different way. Anyone who has witnessed an explosive volcanic eruption from up close, the dull rumbling in reminder that accompanies the outbreak, such as a Subwoofer speaker coming. This low-frequency sound waves are usually in the Vulcan’s throat, if the Magma contained Gas explodes there. In the case of measurements with special microphones volcano, researchers have detected already decades ago, that the energy of these waves is in the for human ears inaudible frequency range of the infrasound at its greatest.
in Order to monitor the activity of mount Etna, found the researchers from Florence in front of more than eight years in two small networks, each consisting of four infrasonic microphones, on the southern slopes of mount Etna. These Sensors recorded all of the low-frequency sound waves continuously, regardless of whether they originated from the volcano itself or, for example, by Storms or other events. With mathematical method, the researchers were able to determine the direction along which the sound waves spread, and to determine whether the infrasound came from the craters in the summit area of mount Etna or not. Finally, Ripepe and his staff compared the measured values with the data from the mount Etna activity recorded in the volcano Observatory in the Sicilian city of Catania continuously.
restrictions for non-explosive eruptions
In the evaluation of the measurement series showed that each explosive eruption of mount Etna has been accompanied, as expected, with strong infrasound waves. As the researchers in the “Journal of Geophysical Research Solid Earth” letter, it turned out that the volcano created a infra-sound waves, for over an hour before he launched the first ash clouds, and lava fountains from its craters. Overall, mount Etna erupted in the measurement period 59 Times explosive. Only one of these eruptions, the network was able to detect any infra-sound waves in front of the outbreak.
