GROUND DEFORMATION IN THE PHLEGRAEAN FIELDS

The geodetic surveillance system of the Phlegraean Fields has been active since the late ‘60s and has evolved in time by updating of the existing systems and implementation of new monitoring systems. This enabled the bradyseism phenomenon in the Flegrean area to be closely monitored, which was characterized by two episodes of exceptional intensity in the years 1969-72 and 1982-84, with maximum uplifts of the crust of about 1.70 and 1.80 metres respectively, both recorded in the Pozzuoli coastal area. They were followed by lowering phenomena (about 20 cm in one case and about 90 cm in the period between 1985 and December 2001), which were much slower than the previous ground rise.

Variations in height calculated at trig. pont no. 25, situated in the area of maximum vertical deformation, actually show the various phases of bradyseism in the Flegrean area. (Source: Monitoring Report 2001)

The lowering phase of the ground, which began in 1985 and is still in progress, has been interrupted by brief uplifting episodes, the most significant occurring in 1989 and 2000, the maximum variation, again in the Pozzuoli area, being of approximately 4-5 cm.