Efficiency Evaluation of the Seismic Monitoring Systems in the Italian Off-Shore as a Feedback for Induced Seismicity Detection Capability within Oil-Gas Exploitation Plants

Session: Mechanisms of Induced Seismicity: Pressure Diffusion, Elastic Stressing and Aseismic Slip [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The Mediterranean Sea hosts very important oil and gas fields, whose exploitation is certainly of primary importance in the framework of energy supply. Many ongoing and potential productive fields lie within seismically active areas of the Italian off-shore, resulting in a two-fold problem: anthropic activities may have impact on hazard, for the potential increase of seismicity rate, while large earthquakes close to operating platforms might stop exploitation, causing loss of investments.

In this framework, the estimation and mitigation of seismic risk and seismic monitoring are key points. The efficiency of a seismic monitoring system is among the common best practice for the safe exploitation of a reservoir. In this study we evaluated the efficiency of the monitoring system in the central Mediterranean off-shore, in terms of earthquakes detection, location and evaluation of magnitude. To do this, we use the time picks from the Bulletin of Italian Seismicity and relocate the off-shore seismicity and performed a deep analysis of hypocentral uncertainties and the magnitude of completeness Mc. We analyzed such performance in the view of the seismic monitoring guidelines of on-shore areas recently published for the Italian territory. In some test areas (Northern Adriatic off-shore, Crotone and South-Eastern Sicily) where exploitation and seismic hazard are mutually significant, the current seismic monitoring level does not match properly the guidelines requirements. The minimum detectable magnitude and the resolution of location estimates sharply decrease moving away from the coastlines, as well as the depth resolution. However, focusing on the test areas, our results encourage a specific focus on the relationships between earthquakes’ location and their distance from the exploitation areas, the spatiotemporal variations of the seismicity ratios, in order to find out any implication useful to discriminate the induced from the tectonic/natural seismicity.

Presenting Author: Mario Anselmi

Authors