GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 1.3 259 the seismic array ARF (Fig. 1). Array ARF is composed by a 18 channels acquisition system with short period seismic sensors. The use of array techniques applied to continuous recorded data has allowed to detect some LF events and an episode of tremor at the beginning of 2015. Data analysis and results. ARF array was installed in the middle of CF caldera (Fig. 1) and is working since 2010 with a great continuity. The detection of volcanic events is performed mainly by array analysis in frequency domain. By evaluating the coherence and propagation properties (slowness and backazimuth) of the seismic wavefield, we can identify transient signals different from seismic noise and potentially interesting for monitoring purposes (La Rocca and Galluzzo, 2012). Signals characterized by coherence higher than a chosen threshold are then observed at the nearby network stations to establish their origin (firs of all if they are natural of artificial events) and main features. Those events possibly related with the volcanic activity, that are any signals compatible with volcanic tremor and LF earthquakes, are further analyzed Fig. 1 – ������� ���������� Seismic monitoring network installed in Campi Flegrei area in 2015. The cyan square in the middle of Campi Flegrei caldera indicates the position of array ARF. The geometrical configuration of array ARF is shown in the lower right corner. Fig. 2 – ��� ��������� Low frequency seismic event recorded at array ARF. The vertical components of each station are shown filtered in 1-5 Hz frequency band.