Earthquakes in Italy are a reminder of an even greater danger: the eruption of the supervolcano. Because the consequences are hard to predict.
The earth in the Naples area is continuously rising – because something is pressing from below: the magma and gases from the supervolcano Campi Flegrei, the so-called Phlegraean fields. In the past few days, there have also been several small earthquakes at shallow depths. Italy’s leading expert says: “So we are in an unprecedented situation.” Experts have been monitoring the region for years, and they increased the warning level in 2016.
The Phlegraean Fields extend 150 square kilometers underground, the earth seems to breathe in the region, rising and falling like a chest as magma flows towards the surface or sinks back down. And now ground elevation is well in excess of previous years, while the subsurface is becoming more active.
From 1985 to 2003, the earth in the region had subsided after previously raising. Since 2005 there has been ground uplift again. “I was hoping that it would end as soon as it reached 1984 levels,” volcanologist Giuseppe De Natale of the National Institute of Geophysics and Volcanology in Rome told the Corriere newspaper. However, the head of the observatory on Vesuvius had to realize: “In the past few months we have exceeded the maximum of 1984, we are now a few centimeters higher.” Ground upheavals are also registered in the Eifel region near the Laacher See, where a super volcano also slumbers underground. A supervolcano is an area of volcanic activity over a particularly large magma chamber, there are around 20 in the world.
Resistance of the rock not infinite
Above the supervolcano Campi Flegrei there is now the highest surface level and probably also the highest internal pressure that mankind has ever experienced – at least in the past two centuries. So this is an unknown situation. However, it is clear that the resistance of the rock is not infinite, according to De Natale. “We don’t know the critical point.”
Therefore, the increasing earthquakes are also given special attention. The activity would be even stronger, in De Natale’s view, if the earth had lifted not only that much, but also very quickly. On March 13, tremors of magnitudes 1.4 and 2.8 shocked people in the region. The first tremor occurred at a depth of 1.9 kilometers and the second at a depth of 2.7 kilometers. The main reservoir of magma is said to be at a depth of seven to eight kilometers. From De Natale’s point of view, there is no evidence that magma has risen to shallow depths below the surface.
“We need to understand the volcano better”
After all, volcanologist De Natale considers an impending “catastrophic eruption” near Naples with a huge ash cloud to be “extremely unlikely”. The last time the Phlegraean Fields erupted so strongly was 15,000 years ago. 39,000 years ago an eruption must have sent the earth into winter: significantly more ash and rock were emitted than in 1815 when the Indonesian volcano Tambora erupted. At that time, Europe and North America experienced a year without a summer. During the last eruption of the Phlegraean Fields in 1538 a new mountain was formed.
In the course of the continuous uplift, the alert level was raised to yellow in 2016 – with the result that the super volcano has to be scientifically monitored. Eleonora Rivalta, professor of earthquake and volcano physics at the University of Bologna and at the Geoforschungszentrum in Potsdam, told the newspaper: “We must intensify our efforts to better understand the volcano.” However, the increased earthquake activity in this seismically highly active zone is not yet a reason to sound the alarm.
