Wednesday , June 16 2021

The massive eruptions of the Italian volcano match the pattern – and the cycle could be resumed

New research indicates that a volcano near Naples in Italy may be at an early stage of preparations for an eruption large enough to change the surrounding landscape.

Research, published today in Progress in science, it can be particularly interesting for 1.5 million people living within the volcanic complex. Fortunately, there is no indication for them that this huge event will take place in the near future. Volcanic eruptions, such as this one, can last thousands of years, and volcanologists can not tell when and even If, this particular type of eruption will occur. Nevertheless, a fascinating and rare look at the guts of one of the most dramatic phenomena on Earth.

In a research. Scientists have found that molten rock (magma) under the Campi Flegrei volcano can slowly rise towards a massive eruption, large enough to create a huge depression in the landscape called the caldera.

From 1912, there were only seven calderous collapses all over the world. Campi Flegrei had at least two major caldera eruptions in its history, including 39,000 years ago, which sent nearly 48 cubic miles of magma to the surface, and another 15,000 years ago released 9.6 million cubic magma. The latter formed the present caldera at Campi Flegrei, which is over eight miles wide.

Today the caldera is home to a regional park, cities, suburbs of Naples and a crater surface that occasionally trembles from earthquakes and sends logs of hydrogen sulphide into the air.

In this study, the researchers studied the rocks from these caldera eruptions – and 21 smaller eruptions from the same volcano – to indicate how the magma tanks at Campi Flegrei changed over time.

"Understanding what melts below the surface is so important to help us predict what volcanoes can do in the future," says Janine Krippner, volcanologist at Concord University in West Virginia. Krippner was not involved in the research. "It's really great research to see all of this data, above all those eruptions that are watched to tell a story."

"Campi Flegrei is unique," says lead author and volcanologist Francesca Forni. Forni began to look at the cycles of forming the caldera at Campi Flegrei as a PhD student at ETH Zürich. For geologists, these two caloric phenomena occurred relatively recently in the last 60,000 years.

This "young" age means that the rocks Forni looked upon were still relatively fresh and did not undergo harmful cycles of deformation and erosion that could have destroyed valuable data. It so happened that Campi Flegrei offered an unusual opportunity to look at the relatively new concepts of the caldera formation cycles.

"In the past, many studies at Campi Flegrei focused on a single eruption or limited period of activity, and this is the first study that takes into account the magma evolution of the system," says Forni.

in 1538 an eruption erupted 403-meter hill in one week

The last time the Campi Flegrei volcano had a significant eruption in 1538, when the eruption built a 40-meter hill in one week. The hill became known as Monte Nuovo, meaning "new mountain". Fornia's research indicates that the conditions during this eruption were similar to those that preceded the caldera.

"Generally, magma wants to explode, they do not like to accumulate in the shell," says Forni. Thus, conditions such as temperature, pressure, gas content and the presence of water must be in order that the magma can grow and ultimately form the caldera. Forni thought that these conditions could be fulfilled after the eruption in 1538, What the volcano means could at that time they launched another caldera cycle.

But time is difficult when we deal with cycles that last longer than any human life expectancy.

"At the moment, we have no restrictions," says Forni. "We do not know when it will break out in the future." They know that the previous caldera cycle lasted 21,000 years, but there is no guarantee that the next one will take the same amount of time. There is also the possibility that the volcano may get extinct before creating another caldera. No more data can currently be detected without more data.

"Volcanoes are not clocks, neither in terms of time nor behavior," says Forni.

This does not mean that people should not do what they can to prepare for the potential risk of caldera eruption.

"These really big eruptions are very low probability," says Krippner. "But if it does, we must know as much as we can." This research enriches this growing knowledge about Campi Flegrei.

Krippner and Forni emphasize that Campi Flegrei's activity is extremely closely monitored by local authorities. They also emphasize that emergency planners are constantly looking for much smaller signs of eruptive activity on the volcano. Preparation for future eruptions, regardless of whether they are wellington boots or something much smaller, is a fact for people living in this area.

"Because the city is built in this caldera, even small eruptions can be very destructive," says Krippner. "Around 800 million people live around volcanoes around the world, in this case they live in one."

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