There are currently about 1,500 potentially erupting volcanoes in the world, with about 50 eruptions occurring each year. Predicting volcanic eruptions is still difficult. A new study recently developed a prediction model that researchers believe more accurately simulates the process of volcanic eruptions and can predict when and where they will occur.
Inside several of the most dangerous volcano categories, domed volcanoes are the most active. The researchers found that the summit of such volcanoes actually creeps out some sticky magma before erupting, forming rounded protrusions. This magma is too thick to flow. But eventually, the energy stored inside will break through these round protrusions, spewing hot gas, ash and lava debris, like a high-speed train, rushing down the slope of the mountain.
This new study analyzes these round prominences by installing high-resolution cameras and using drone photography in the field at Colima, Mexico; Mount Merapi, Indonesia; Bezymianny, Russia; and Lascar and Lastarria, Chile. A variety of methods were used to analyze the pattern of changes in these round prominences from the beginning of the emergence phase to the final eruption phase.
They found that even for the same volcano, these round, viscous protrusions do not emerge at the same location before each eruption. Sometimes at the top of the mountain, other times on the flanks of the mountains. This made the researchers wonder: this magma is transported to the crater by magma pipes inside the volcano, and if it appears in a different location each Time, does this mean that the orientation of these magma pipes is always changing?
The researchers found an explanation in terms of internal pressure distribution. They found that the pressure distribution inside the magma is constantly changing as it is expelled, leading to changes in the orientation of the magma pipes. This study also found that there was a pattern to this change.
This study used the patterns found, the depth of the magma source, the density of the crust beneath the volcano, the size of the magma savings pool, and a host of other parameters to build a model. Using all possible combinations of parameters, the researchers ran up to several million simulations to obtain a relationship between the frequency and size of volcanic eruptions. They saw that this relationship matched the estimates made using historical data. The team believes that they have finally found the basic pattern of the eruption mechanism of the volcano.
They also found that the relationship between eruption size and frequency was again different for volcanoes located in different regions. They believe that this is also related to the state of the crustal plate junction in each region. They will further integrate this part of the parameters and information into the model they built in a follow-up study.
Using this model to predict the frequency and size of volcanic eruptions will effectively help people assess the risk of volcanic eruptions, the researchers said. Nearly one billion people in the world now live near volcanoes.
The research team mentioned the case of Mexico City. It is densely populated, and the city is surrounded by several active volcanoes, including Nevado de Toluca, which has not erupted for about three thousand years. The study concluded that there is a process of about 10 years between the time a protrusion of dense magma emerges from the crater and the eruption of the volcano.
The study says this information helps Mexico City eliminate the need for immediate evacuation arrangements when it sees changes in the crater. “Once the volcano starts to move, you know there’s a decade after that.” said Luca Caricchi, a professor of volcanology at the University of Geneva, one of the researchers.
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