Optimal Design for Expanding a Microseismic Monitoring Network on an Unstable Rock Face in Northern Italy

Microseismic monitoring is an efficient method in understanding the stability of rock slopes and it has been increasingly applied in this field in recent years. An optimal network distribution could effectively improve the efficiency of a microseismic monitoring system, especially to increase the localization accuracy of seismic events. In this work, the widely accepted guidelines were used to densify a microseismic network composed of five three-component geophones, which has been working on an unstable rock face in Northern Italy since 2013. The existing 5-geophone network was progressively expanded to a 15-geophone network. The location accuracy was calculated by using synthetic data for each network. We compared the location accuracy for different networks to estimate their performance. The results showed that the additional geophones could decrease the location errors from 12–24 m for the 5-geophone network down to 4–6 m for the 15-geophone network. We also compared the channel performance of the five three-component geophones to select the channels that should be retained in the future expanded network.