A team of researchers from the University of Illinois discovered how to identify the signals of an imminent eruption in the case of “Silent” volcanoeswho errocate without notice, with serious risks for local populations. The study, published in the magazine Frontiers in Earth Scienceis based on the analysis of the Vulcano Veniaminoflocated in theArchipelago delle Aleutinein Alaska. This volcano, despite being carefully monitored for decades, in most cases gives rise to explosive eruptions without giving signals significant (Stealthy Eruptions). His study highlighted that these eruptions occur in the presence of a Low Magma flow and when the magmatic room has small size It is a certain shape and depth. Identifying the internal characteristics of these volcanoes therefore represents the first step for the prevention of volcanic risk.
The study of Vulcano Veniaminof
The Vulcano Veniaminof He is one of the most active volcanoes of Alaska. In recent decades, it has produced numerous explosive eruptions of moderate intensity, with the emission of columns of ashes up to 15 km high able to interfere with air traffic and represent a danger to the population. The researchers analyzed the monitoring data prior to the 2018 eruption, which did not show significant signals. Then they used them to create a Vulcan behavior model in the presence of different conditions. In particular, six different potential dimensions and shapes of the magmatic chamber have taken into consideration.
The simulations have shown that a high influx of magma in the magmatic chamber increases the deformation of the soil and the probability that an eruption will occur. Even a significant influx of magma in a particularly small magmatic chamber increases the probability of an eruption. In both cases, a soil deformation occurs, which represents an important precursor phenomenon for the provision of an eruption. When instead you have a Low Magma flow in one relatively small magmatic chamberit becomes more likely that an eruption take place without any notice. Vulcano Veniaminof, for example, has a small magmatic chamber and a low magma flow. Also the shape of the magmatic chamber It has a role: if it is large and flat before the eruption, earthquakes can occur, while if it is elongated, soil deformations may occur. The “silent” eruptions therefore occur in the presence of a low flow of magma, but also when the magmatic chamber has certain dimensions, shape and depth. The researchers found that another important factor is the Rock temperature in which the magmatic tank is located. When the magma is long, by increasing the temperature of the rocks, it is less likely that these will be fractured by generating earthquakes or that the soil deforms: you can thus have a sudden eruption.
The implications of the study
Among the “silent” volcanoes of the planet there are the Popocatépetl and Colima in Mexico, the Merapi in Indonesia, the Galeras in Colombia and also it Stromboli in Italy. Often the surroundings of these volcanoes are inhabited, so it is very important to acquire useful elements to predict their eruptions. The study of the Alaska volcano, therefore, could contribute to improve monitoring of other volcanoes that behave similarly, starting from the knowledge of their internal structure and their diet. To reduce the consequences of these sudden eruptions it is necessary to use particularly precise and advanced tools, able to grasp even the most modest signals. For example, they can be used clinometers To measure the variations in the inclination of the soil and extensimmers To detect its deformation, but more advanced techniques such as the Infratsuoni monitoring.
