Santorini volcano: Scientists warn of a possible new explosion

File photo: EUROKINISSI
File photo: EUROKINISSI

The subsoil beneath the bottom of the Santorini caldera “photographed” scientists revealing a cylindrical disorder at the point of the rise of the magma, which had caused the alarming earthquake-volcanic eruption of 2011-2012.

For the first time, scientists, Greeks, Americans and Britons, “enlightened” the geometry of the magmatic chamber of the active volcano with the aid of the technique of seismic tomography, which made it possible to “photograph” what is happening in the subsoil below its bottom caldera.

Below the cylindrical disorder of disturbed rocks, new magma accumulates slowly, according to scientists. The new study, which is extremely important for the assessment of future volcanic eruptions, shows, among other things, that any corresponding large-scale future volcanic eruption, whenever it happens, is likely to occur in the same caldera region.

Researchers at the University of Oregon, the Imperial College of London, the Aristotle University of Thessaloniki and the University of Athens, scientifically responsible for the US Deputy Professor Emily Huff, published the publication in the Earth Sciences and Earth Sciences Letters International Journal of Geosciences EPSL).

For research, in the framework of the PROTEUS seismic experiment, which took place in the caldera of Santorini in November and December 2015 and the first results are only now known, the American oceanographic vessel “Marcus Langseth” was used, while more than 90 underwater and 60 ground seismographs in the wider region of Santorini.

“We found a cylindrical anomaly, three kilometers in diameter, stretching from the surface up to a depth of about three kilometers, in the northern basin of the caldera of Santorini, just above the point of the magma, which was responsible for the earthquake-volcanic 2011-2012, “she told the Athenian and Macedonian News Agency, the American professor who had lived in Greece for 20 years studying Bronze Age archeology before turning to the geosciences. j volcanology. Today he specializes in the “photographing” of the magmatic chambers under the volcanoes, especially the submarines, which he had done before the Santorini in the Southwest Pacific and other oceans.

 

“This anomaly,” he added, “corresponds to a material of very low density, with a large porosity between 4% and 28%, which has pores filled with hot sea water. We conclude that the collapse of a certain area of ​​the caldera floor created a low density roller with high porosity material. It is striking that the positions of the pipelines related to the first three phases of the Minoan eruption of 1600 BC are in the same position as the one of the anomaly we have identified. “

This association between the earlier volcanic pipelines of the great eruptions of the past and the current anomaly in the northern caldera of Santorini suggests that it is probably a geological structure that exists for a long time.

“Knowing the geometry of the magmatic chamber allows for better estimates of the volcanic potential. In any case, it is clear that since the anomaly identified is linked to the location of the pipelines of the largest volcanic eruptions of the past, any corresponding large-scale future volcanic eruption, if ever, will probably be in the same area, “he told RES-MPA is the assistant professor of the Department of Geology and Geoenvironment of the University of Economics, Paraskevi Nomikou , member of the research team.

“The results of the research are of great importance for the assessment of future volcanic eruptions. The lack of pressure in Santorini’s Northern Basin, due to the cylindrical abnormality detected by tomography, functions as a local ‘pump’. As a result, the magma rises either on the surface through the Nea and the Old Kameni rupture, leading to relatively small volcanic eruptions such as those of 1707, 1886, 1925 and 1939, whether concentrated near the anomaly, as in the earthquake-volcanic eruption of 2011-2012, “Professor of Geophysics of the Department of Geology, AUTh, Kostas Papazachos , also a member of the research team.

“We see,” he added, “that seismic tomography works as a” diagnostic tool “, as do the various types of medical tomography, eg. magnetic resonance imaging. By locating subsoil areas with high and low seismic velocities, we study the geological structure of the subsoil, but at the same time we understand the future behavior of the volcano, as the physician uses medical tomography to understand the cause and the development of a disease. “

The volcanoes, such as Santorini, have caused decades of interest to scientists trying to decode their way of creating them. Although the predominant scientific view is that the corridors are formed by the collapse of the roof of the volcanic cone, after evacuation of the magmatic chamber underneath the cone, the various mechanisms of the caldera formation are still the subject of discussion because they present differences affecting both the evolution of the caldera, and the “recharging” of the magma chamber before the next volcanic eruption.

“The underground density abnormalities discovered in the new research,” according to P. Nomikos, “can influence magma concentration between volcanic eruptions, indirectly affecting future events of volcanic activity.” A conclusion that researchers believe is extremely important for both Santorini and other global volcanoes.

Source- iefimerida.gr 

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