Feedback Responses Between Endogenous and Exogenous Processes at Campi Flegrei Caldera Dynamics, Italy

Abstract

The Campi Flegrei caldera is characterized by the phenomenon of bradyseism, as evidenced by stratigraphic records of alternate oceanic and continental sediments. Since 2005, increasing volcanic deformations around the region, have resulted in a growing concern over the dense population in the inhabitation. Studies have highlighted that the caldera dynamics are driven by a combination of endogenous processes and modulation phenomena induced by exogenous processes e.g. rainfall, atmospheric pressure and tidal loading, etc. Although the complex feedback mechanisms of both endogenous and exogenous processes are still under debate, the present study is focused on the increased potential of modulation due to exogenous processes with the evolution in the degree of inflation of the magma chamber. Specifically, Campi Flegrei volcanic system shows sensitivity to seasonal hydrological cycles during slower rates of inflation and to short-period tidal modulations during higher rates of inflation. A cyclic opening and sealing of fractures by volatile outgassing and silicate settling may produce episodic behavior. The seismicity in relation to exogenous processes imposed by seasonal rainfall and tidal loadings shows that the degree of correlation depends on the different inflation rates finally interpreted in the fault resonance destabilization model framework, under rate-and-state dependent frictional formalism.