When his phone rang at 3.22am last Wednesday, Giuseppe Salerno, 50, head of volcanologists at the National Institute of Geophysics and Volcanology of Catania (INGV), had already risen after a thunderous roar awakened many of the city’s inhabitants. The call came from the headquarters of the INGV where, a few seconds before that disturbance, seismic waves from one of the 40 monitors in the operating room seemed to jump off the screen. For the fourteenth time in less than a month, Etna sent another reminder that it is one of the most active volcanoes in the world.
Etna, 3,300 meters above sea level, has been in explosive form in recent weeks, spewing incandescent magma and a copious ash shower that has reached Catania. Since February 16, with meticulous precision, every 48 hours the volcano has mounted a fireworks display with lava fountains that reach 2,000 meters in height.
For three days, The Guardian had access to the rooms of the INGV in Piazza Roma, Catania, where 100 Italian scientists monitor the movements of Etna day and night in an attempt to explain these recent phenomena.
“The recent activity is part of a so-called lava outbreak that is among Etna’s normal activities,” says Salerno, a former doctoral researcher in the department of geography at the University of Cambridge. “What is really peculiar is that the volcano is behaving like a machine, with rhythms that have almost mathematical precision. That is why we have been monitoring every breath, rumbling and shaking for the past few months. “
The information recorded by the 150 monitoring stations located in the 460 square miles of the volcano, including cameras with heat sensors, gas emission detectors and seismographs, is sent in real time to the control room and transmitted in dozens of monitors, they give the impression. from a war room in a spy movie.
“You have to imagine this control room as a hospital,” adds Salerno, “with dozens of doctors working for the same patient: Etna, which in recent weeks has been showing peculiar symptoms. From here we can control their heartbeat with seismographs or their breathing with gas detectors ”.
The recent eruptions have caused some distress for the people who live on the volcano., with ash rains that have covered streets, squares and buildings. Only in recent weeks in the town of Giarre more than 12,000 tons of ash have fallen. “It is an extremely dramatic situation, an emergency, says Alfio Previter, a municipal official. Salerno said: “We are literally buried, and if this continues, many cities will go bankrupt in their attempt to remove the ash, which could cost hundreds of thousands of euros.”
According to Italian law, the ash collected in the streets and squares, and mixed with other forms of urban waste, is considered a special waste, which increases the cost of its disposal. Proper disposal of one cubic meter of volcanic ash costs around € 20 (£ 17).
However, Salerno, whose career has taken him to Kilauea in Hawaii and the volcanoes of Central America, explains that the key to unraveling the mystery of Etna’s unusually spectacular eruptions is precisely the ash from the volcano.
In an underground INGV laboratory, Lucia Miraglia, 53, a geologist and volcanologist who has studied Etna ash under a microscope for the past 20 years, recently made a revealing discovery: “By studying the ash that has fallen in recent days, we note that it reflects what volcanologists call “primitive magma”; that is, a magma that comes from the bowels of the mountain and carries a greater gas charge, which is why we are seeing these surprisingly high lava fountains. This type of fresh magma has been seen before, but the peculiar thing is that the magma that Etna has been spewing since February 16 is the most primitive that I have studied in the last 20 years ”.
Etna’s magma originates from various deposits located miles underground. INGV experts estimate that Etna’s main reservoir, and also the largest, is 12 km (7.5 miles) underground. Sicilian geophysicist Rosanna Corsaro, who studies Etna’s core from INGV headquarters, says: “The magma that has been emerging in these recent eruptions appears to come from about 10 km underground.”
Recently, Etna has gone through a period in which there is a very efficient transfer of magma from the depths of the surface. The southeastern crater, which has been spewing lava in recent weeks, has so far been functioning as a safety valve. However, other scenarios cannot be excluded. “Sometimes, the eruptions of primitive magma are lateral: that is, when fractures appear in the slope of the volcano and give rise to this type of activity,” says Corsaro. “It could be that at a certain point this valve is no longer working efficiently. In that case, if the primitive magma continues to rise to the surface, it could form a side opening. “
Such “flank eruptions” are the ones that volcanologists fear most, as lava flows down the sides of the volcano, opening fractures in the low mountains that risk flooding the cities below.
Forty years ago, shortly after lunch On March 17, 1981, a lateral eruption unleashed one of the most dramatic lava flows in the volcano’s history.. Fortunately, it lasted only a few days, but its volume buried forests, houses, streets and railways, threatening to transform the small town of Randazzo into a new Pompeii. Estimates of the total volume of lava in that event are in the range of 30 cubic meters (1 billion cubic feet).
But The most destructive flank eruption occurred in 1669., when the lava, accompanied by earthquakes, buried dozens of villages and even reached the sea.
“At this time, the recent activity of the volcano does not suggest that there will be an eruption on the flank,” says Stefano Branca, director of the INGV in Catania. “However, it is clear that Etna is no stranger to lateral eruptions. It is not a question of risk: lateral eruptions will occur at some point in the future.
“When?” he adds. “Well, God only knows when.”
George is Digismak’s reported cum editor with 13 years of experience in Journalism