Surface seismic monitoring of a natural gas storage reservoir in the Po Plain (northern Italy)

In the framework of the pilot project for CO₂ geo-sequestration in the depleted gas storage field of Cortemaggiore (Po Plain, northern Italy), started by the Italian company STOGIT in 2004, a surface seismic monitoring has been planned. The monitoring aims to detect possible changes, especially in microseismicity of the area, caused by the injection activity designed to achieve CO₂ geo-sequestration at 1000-1500 m of depth. The monitoring focuses on the ground motion produced by small-magnitude, shallowdepth seismic events. The Milano department of the "Istituto Nazionale di Geofisica e Vulcanologia" is taking part in the project through the installation of a seismic network, consisting of three surface and four 100-m deep borehole sensors, located at distances ranging from 0.5 to 3.5 km from the planned injection point. In this work, we analyze the data recorded from May 2010 to April 2012, in order to determine the noise levels of the area and the detection capabilities of the network.