Testing and optimization of the seismic networks of Campi Flegrei (Southern Italy)

Abstract

. The definition of the network resolution power is an important parameter to be considered when evaluating most of the seismic analysis, being connected to the location quality and earthquakes detectability. We estimated the resolving power of the seismic network of Campi Flegrei. The results show that the actual moment magnitude threshold is 0.5 in the Solfatara area, center of the caldera, but increases sharply going away from the center. We also estimated the theoretical resolution power of the actual seismic network of Campi Flegrei plus 5 hypothetical borehole stations, moving the borehole stations into 3 different wells. As expected, big improvements in the location parameters come from the use of borehole stations. The results show that a 3000 m deep borehole located close to the actual hypocentral area would allow to detect and locate the very low magnitude earthquakes, probably connected to the hydrothermal system characterizing the Campi Flegrei caldera. Finally, we performed an optimization analysis of the permanent seismic network of Campi Flegrei finding the best 3 station positions that would increase the resolution power of the network to locate earthquakes in the South and offshore part of the caldera. We evidenced that the actual network has an improvable resolution in the South and West part of the caldera