Some considerations on background noise and detection capability of the “San Potito- Cotignola seismic monitoring network”

We have developed an analysis of the “San Potito e Cotignola” monitoring network (SPCSN) and its detection capabilities. This is the minimum value of magnitude that the network can detect at a given point in space depending on its geometry and density and the background noise level at each station, which in turn depends on the characteristics of the subsurface.
The following conclusions can be drawn from this:
• In general terms, the study area could present a number of objective difficulties, mainly related to the high degree of anthropization as well as a considerable sediment thickness in the region;
• Despite this situation, the PSD functions of the noise at the 10 stations of the network show that they are within the standards established by the Peterson NLNM and NHNM models throughout the frequency range of interest, although in some cases, e.g. at station SP01, the values approach or exceed the NHNM model;
• Background seismic noise is the factor that most affects the overall performance of the network, and the detection threshold deteriorates significantly (i.e., the minimum detection magnitude increases) the stronger the seismic noise is;
• Our study suggests that ML~ 0.1 is the minimum detectable magnitude for precisely localized earthquakes (i.e., determined by at least four stations and with SNR = 3) occurring on 100% of the reservoir area and 90% of the inner domain (ID);
• Based on the same criteria, the estimated minimum values for the detectable magnitude in the Extended Domain (ED) are between ML ~ 0.6 -1.2.
• The network is capable of detecting events with ML~ 0.1 almost for the entire alert area (including the extended domain (ED) around the storage), with the number of triggered stations at 33%.