Press
The situation at the supervolcano of the Phlegraean Fields is getting worse. The uplift rate has increased dramatically. Scientists speak of a “magma lens” underground.
Pozzuoli – The Phlegraean fields in the south of Italy do not rest. One swarm of earthquakes after another is shaking the bay around the port city of Pozzuoli all the way to the west of Naples. On Wednesday morning (April 24th) at 6:20 a.m. there was the strongest earthquake in 24 hours in the sea off the coast with a magnitude of 2.1.
The earthquakes are the side effect of the phenomenon of bradyseismos, which describes the rising and falling of an area over a magma deposit caused by volcanism. This uplift is usually caused by magma intrusion from depth from a deeper reservoir to a less elevated reservoir, which can result in a volcanic eruption.
Latest monitoring report from the supervolcano in Italy raises alarm bells
But liquid magma also has the property of secreting water and gases or heating groundwater, which also leads to expansion. In any case, the Phlegraean fields are currently in a massive uplift phase.
![A new video documentary simulates a volcanic eruption in the Phlegraean Fields.](https://www.merkur.de/assets/images/34/393/34393868-eine-neu-videodoku-simuliert-einen-vulkanausbruch-der-phlegraeischen-felder-QpBG.jpg)
The latest weekly report from the National Geophysical and Volcanological Institute (INGV) raises alarm bells for the approximately 500,000 residents of the “Red Zone”. The rate of uplift at the supervolcano has quadrupled, and the entire bay is rising faster than it has in decades.
![Graphic shows the accelerated uplift rate of the Phlegraean fields](https://www.merkur.de/assets/images/34/413/34413283-grafik-zeigt-die-beschleunigte-hebungsrate-der-phlegraeischen-felder-PEBG.jpg)
In recent months, the ground around Pozzuoli has risen by an average of one centimeter per month; the measurements take place in the Rione Terra district near the coast. Between April 9 and 10, the bay jumped one centimeter in just two days. Between April 15 and 16, another jump of half a centimeter was recorded.
The entire bay is arching faster and faster over the supervolcano
“These two episodes were also reported by the other nearby stations within a radius of approximately two to three kilometers,” the report said. However, the values decrease outwards from the center of the uplift in Pozzuoli. The summary: “Overall in the last 15 days there has been an uplift in the area with maximum deformation of around two centimeters.”
Calculated per month that would be four centimeters. However, a realistic and reliable estimate of the average monthly uplift rate can only be made with the data for the coming weeks. Since 2005, the ground level has risen 1.26 meters. That's 31.5 centimeters above the record set in the 1980s, when Pozzuoli was evacuated due to concerns about an impending volcanic eruption. In the 1950s it was even four meters lower.
![The quakes from the supervolcano have destroyed the masonry of the port church of Pozzuoli.](https://www.merkur.de/assets/images/34/255/34255148-die-beben-des-supervulkans-haben-das-mauerwerk-der-hafenkirche-von-pozzuoli-zerruettet-2kckHPfBlKBG.jpg)
The President of the INGV Carlo Doglioni explained in an interview with the science portal geopop.it Earlier this week, the uplift in the Phlegraean fields is “currently four centimeters per month,” meaning the pace has quadrupled. Another value has also increased: at the steam outlet points (fumaroles) of the Solfatara, the average temperature at a height of five meters has risen to 95 degrees; previously it was one degree lower. The hot springs have dried up, so there is less water underground.
Magma lens at a depth of four kilometers is still blocked by porous rock
“What we observe does not completely reassure us,” says Doglioni. The acceleration of ground uplift “has objectively put us in a state of even greater alertness.” As for the cause, he has two models ready: “One says that there is a magma lens that is at depth, about four kilometers deep, in the “Sediment series penetrates”.
“Others believe that this bulging is related to the pressure of the fluids.” Doglioni's personal interpretation is that there is a “seal about four kilometers deep” that is holding back the magma, which is causing the quakes. “However, there are also eruptions that can come from the deepest magma chamber, which should be around seven to eight kilometers deep.” A study warned last year that the rock that blocks the magma could become brittle.
As a result, magma is present, so an eruption cannot be ruled out. But: “We are talking about very small volumes.” Large eruptions such as the apocalyptic eruptions in the Ice Age required volumes of tens, if not hundreds, of square kilometers.
Recently, a simulation of a maximum eruption of the supervolcano by Swiss television caused an uproar throughout Italy. Doglioni: “Currently there are magma quantities of less than one cubic kilometer, perhaps even only tenths of a cubic kilometer, i.e. very small volumes that cannot cause large eruptions.”
Volcanic crater is reminiscent of the last eruption – is there a magma giant slumbering beneath it?
An eruption that could occur in the Phlegraean Fields in the near future would be more similar to that of Monte Nuovo in 1538, which was localized and announced in such a way that local residents could escape. “So much smaller and with a very limited volume and limited damage.” The Science Channel Geopop.it had recently simulated a smaller eruption. Doglioni is currently more concerned about the risk of earthquakes.
![The crater of Monte Nuovo is best seen from the air as an extinct volcano.](https://www.merkur.de/assets/images/32/926/32926659-der-krater-des-monte-nuovo-ist-aus-der-luft-am-besten-als-erloschener-vulkan-zu-erkennen-2sUb67ayeWBG.jpg)
According to an INVG study last year, the eruption of Monte Nuovo in 1583 was just an aborted large eruption in which only a hundredth of the amount of magma was ejected. At that time there were warnings of a “disguised deeper magmatic recharge”. Another study recently discovered a second dangerous structure underground.
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