Campi Flegrei is a nested caldera in Italy, whose structure includes submerged and continental parts at the western edge of the Bay of Naples. Together with Vesuvius and Etna, it is one of the Italian GeoHazard Supersites. The last eruption took place in 1538 A.D. and since then intense degassing, seismic swarms and several episodes of ground uplift have been observed. The area is characterized by one of the highest volcanic hazard in the world, due to the very high density of inhabitants. A major unrest episode took place in 1982-84, when the town of Pozzuoli, located at the caldera center, was uplifted by 1.80 m (~1 m/yr). During the following decades the area has been generally subsiding but minor uplift episodes of the order of few cm, seismic swarms and degassing episodes took place in 1989, 2000-01 and 2004-06, showing that the caldera is in a critical state on the verge of instability. Since March 1970 leveling surveys were regularly carried out to monitor the elevation changes. In the following decades many efforts have been done to monitor the different aspects of the activity of the area, and nowadays Campi Flegrei is subjected to intense geodetic, geophysical and geochemical monitoring. In the last 30 years a number of geophysical investigations has provided important constraints to the description of the subsurface structure and the historical volcanic activity. Surface deformation, microgravity changes and geochemical anomalies at Campi Flegrei have been interpreted either in terms of instabilities of the hydrothermal system or variations in the magmatic source. In particular, discerning between magmatic vs hydrothermal origin of the source responsible of the large uplift episode during 1982-84 (most probably due to deep magmatic source) and of the mini-uplifts (e.g. 2000 and 2004-06, most probably due to pressure variations in the shallow aquifer) may have important implications in terms of civil protection. In the last two decades, the precise and large coverage InSAR technique results to be one of the most reliable tool for mapping the surface deformations and therefore for understanding the volcano dynamics. In addition to optimal data, characterizing the origin of deformation is of major importance for assessing the Campi Flegrei volcanic hazard, since the more realistic is the model employed (with parameters constrained by multidisciplinary data), the more reliable are the results and the ensuing interpretations. In the present work we show the contribution from different monitoring techniques, either in situ or from remote, in order to constrain the source of the activity at Campi Flegrei. In particular, we examine more deeply the contribution from geodesy. We consider leveling and EDM data for the large 1982-84 uplift and InSAR time series for the recent activity (2004-06 and ongoing uplifting detected by COSMO-SkyMed satellite). The use of modern satellite and ground-based geodetic techniques is a formidable tool to understand the state of activity of this volcanic area, providing a great contribution to the mitigation of risk.
Investigating the activity of the Campi Flegrei caldera (Italy) through remote and in situ sensors
BONAFEDE, MAURIZIO;
2013
Abstract
Campi Flegrei is a nested caldera in Italy, whose structure includes submerged and continental parts at the western edge of the Bay of Naples. Together with Vesuvius and Etna, it is one of the Italian GeoHazard Supersites. The last eruption took place in 1538 A.D. and since then intense degassing, seismic swarms and several episodes of ground uplift have been observed. The area is characterized by one of the highest volcanic hazard in the world, due to the very high density of inhabitants. A major unrest episode took place in 1982-84, when the town of Pozzuoli, located at the caldera center, was uplifted by 1.80 m (~1 m/yr). During the following decades the area has been generally subsiding but minor uplift episodes of the order of few cm, seismic swarms and degassing episodes took place in 1989, 2000-01 and 2004-06, showing that the caldera is in a critical state on the verge of instability. Since March 1970 leveling surveys were regularly carried out to monitor the elevation changes. In the following decades many efforts have been done to monitor the different aspects of the activity of the area, and nowadays Campi Flegrei is subjected to intense geodetic, geophysical and geochemical monitoring. In the last 30 years a number of geophysical investigations has provided important constraints to the description of the subsurface structure and the historical volcanic activity. Surface deformation, microgravity changes and geochemical anomalies at Campi Flegrei have been interpreted either in terms of instabilities of the hydrothermal system or variations in the magmatic source. In particular, discerning between magmatic vs hydrothermal origin of the source responsible of the large uplift episode during 1982-84 (most probably due to deep magmatic source) and of the mini-uplifts (e.g. 2000 and 2004-06, most probably due to pressure variations in the shallow aquifer) may have important implications in terms of civil protection. In the last two decades, the precise and large coverage InSAR technique results to be one of the most reliable tool for mapping the surface deformations and therefore for understanding the volcano dynamics. In addition to optimal data, characterizing the origin of deformation is of major importance for assessing the Campi Flegrei volcanic hazard, since the more realistic is the model employed (with parameters constrained by multidisciplinary data), the more reliable are the results and the ensuing interpretations. In the present work we show the contribution from different monitoring techniques, either in situ or from remote, in order to constrain the source of the activity at Campi Flegrei. In particular, we examine more deeply the contribution from geodesy. We consider leveling and EDM data for the large 1982-84 uplift and InSAR time series for the recent activity (2004-06 and ongoing uplifting detected by COSMO-SkyMed satellite). The use of modern satellite and ground-based geodetic techniques is a formidable tool to understand the state of activity of this volcanic area, providing a great contribution to the mitigation of risk.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
