Phlegraean Fields: A volcano that really threatens Naples?

The Phlegraean Fields: An Overview

Geographical Location

The Phlegraean Fields (Campi Flegrei) form a vast volcanic area located in Campania, Italy, west of the city of Naples. They stretch along the Tyrrhenian coast from Naples to Pozzuoli and Cape Miseno, and extend underwater into the Gulf of Pozzuoli.

Etymology

The name comes from the Greek phlegraios, meaning "burning." The Greeks referred to this region of smoldering lands, where hot soil and gas emissions evoked the underground forces of mythology.

A Gigantic Caldera

What is a Caldera?

Calderas are geological depressions formed by the collapse of the ground after a major volcanic eruption when the magma chamber empties abruptly. They provide valuable insights into past eruptions and the evolution of the volcanic landscape over time.

Two Major Eruptions

The Phlegraean Fields caldera, about twelve kilometers wide, formed during two extremely violent eruptions: the Campanian Ignimbrite eruption, approximately 39,000 years ago, and the Neapolitan Yellow Tuff eruption, about 15,000 years ago. Since then, numerous secondary cones and craters have formed within the depression.

Solfatara

An Active Crater

The most famous site in the region is Solfatara, a volcanic crater located within the caldera, near Pozzuoli. It is characterized by the emission of sulfurous gases, steam, and boiling mud.

Geothermal Activity and Bradyseism

Hot Springs and Fumaroles

The Phlegraean Fields are known for their geothermal activity: hot springs, fumaroles, and solfataras. These phenomena result from the heat and gases released by the deep magmatic system. They are harnessed for geothermal, energy, and therapeutic purposes.

Bradyseism

The region is also characterized by a slow phenomenon of uplift and subsidence of the ground, known as bradyseism, particularly visible in Pozzuoli. These deformations, often accompanied by earthquake swarms, are linked to the activity of the magmatic and hydrothermal system beneath the caldera.

History and Archaeology

A Land Inhabited Since Antiquity

The region has been inhabited since ancient times, attracted by the fertility of the volcanic soil. Greek colonists founded Cumae, one of the oldest Greek colonies in Italy, famous for its Sibyl. The Romans developed the thermal resort of Baiae and the port of Pozzuoli, and Lake Avernus was reputed to be an entrance to the Underworld.

The Famous Neighbor: Vesuvius

The Roman cities of Pompeii and Herculaneum, buried in 79 AD, are not part of the Phlegraean Fields; they were destroyed by the eruption of Vesuvius, another volcano in the Bay of Naples. These two neighboring volcanic systems make the region one of the most exposed in Europe.

Risks and Volcanic Monitoring

A Recent Eruption: Monte Nuovo

The last eruption of the Phlegraean Fields occurred in 1538: it created the cone of Monte Nuovo, the "new mountain," in just a few days.

A Natural Laboratory Under Surveillance

Due to their continuous activity and the dense population in the surrounding area, the Phlegraean Fields represent both a major volcanic risk and a natural laboratory for the study and prediction of eruptions. Scientists closely monitor ground deformation, seismicity, and gas composition to detect signs of a possible resumption of activity. This constant monitoring is essential for the safety of the inhabitants.

Landscapes and Exploration

Hiking and Discovery

The region offers unique landscapes, remarkable geological formations, and numerous opportunities for hiking and exploration, from the Solfatara crater to crater lakes and archaeological sites.

Volcanism Around the World

A Geologically Alive Planet

There are approximately 1,500 active terrestrial volcanoes, about sixty of which erupt every year. The Phlegraean Fields fit into this global context of active volcanism, reminding us that Earth remains a geologically alive planet.