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Solfatara is a shallow volcanic crater at Pozzuoli near Naples, part of the Phlegraean Fields or Campi Flegrei volcanic area. It is a dormant volcano that still emits jets of steam containing sulfurous fumes.
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According to the Italian National Institute of Geophysics and Volcanology (INGV), a magnitude 4.0 earthquake struck south of Naples, Italy, on Tuesday, just days after the volcanic region experienced its strongest earthquake in 40 years.
According to the Italian fire department, there was minor damage to buildings in the recent earthquake, but no people were injured. The magnitude 4.2 quake on September 27 shook the region and was felt as far away as Rome.
Campi Flegrei, also known as the Phlegraean Fields, is a volcanic area that includes several ancient volcanoes dating back 39,000 years.
Seismic activity in the region, which stretches for 200 kilometers (125 miles) beneath the Bay of Naples and the islands of Ischia and Capri, has increased this year, with the region experiencing many small earthquakes before the last two. Campi Flegrei experiences a seismic phenomenon known as bradyseism, characterized by cycles of uplift and gradual subsidence of the ground.
The last major eruption of Campi Flegrei occurred in 1538, creating a new mountain in the bay. So far, 2,868 earthquakes have been recorded in Campi Flegrei in 2023 – 1,118 in August alone.
Carlo Doglioni, head of the INVG, gave testimony on the possible outcomes to the lower house of the Italian government’s environmental commission on September 28th.
“There are two possible scenarios for the development of the situation in the Campi Flegrei: the best is that the ongoing bradyseism crisis ends like 1983/84, the worst is an outbreak similar to that of 1538,” he said.
“It is a development that we are not aware of and that we are observing.”
During the 1983–1984 bradyseism episode, the ground rose 3.5 meters (11.5 feet).
The INGV has asked the municipality of Naples to evacuate some residents near the volcanic area to check the most vulnerable places to underlying structural damage from the rising ground. Most of the structures in question were built in the last 20 years.
Italy’s civil protection agency estimates that at least 800,000 people live in a designated “yellow zone” and 500,000 in the “red zone,” the highest risk area near the seismic region.
The last time an evacuation plan was tested was in 2019. However, residents demanded an updated plan outlining what would happen in the event of an eruption.