Analysis and interpretation of induced micro-seismicity by flooding of the Gardanne coal basin (Provence - Southern France)

Emanuela Matrullo (1) , Isabelle Contrucci (1) , Pascal Dominique (2) , Mustapha Bennani (1) , Hideo Aochi (2) , Jannes Kinscher (1) , Pascal Bernard (3) , Pascal Bigarre (1)

1 INERIS - Institut National de l'Environnement Industriel et des Risques
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
3 IPGP - Institut de Physique du Globe de Paris

Mining activity in Provence has left many underground voids that can cause land subsidence or collapses in areas of high population density. In the abandoned coal basin of Gardanne, the flooding of mine voids and fluctuations in the groundwater level induced many seismic events that have been recorded since the beginning of operational monitoring. An example is the seismic crisis of November 2012, where magnitude events > 2.5 were felt by the population. In this context, the objective is to understand the mechanisms of the observed seismicity. This will clarify the relationships between seismicity and rising waters in old mine working, geology and local tectonics. This general aim will be pursued, thanks the availability of the high quality dataset of recording from the dense arrays managed by INERIS and BRGM. We will focus on the spatio-temporal distribution of the seismicity, which allows to monitor the dynamics of faulting and to estimate the extension and mode of rupture of the fracture system. The present work is based on the observation and the characterization of the microseismicity in terms of the accurate hypocentral locations, local and moment magnitudes and focal mechanisms determination in order to characterize the status of the abandoned mine.

Domains: Sciences of the Universe [physics]; Earth Sciences

Emanuela Matrullo, Isabelle Contrucci, Pascal Dominique, Mustapha Bennani, Hideo Aochi, et al.. Analysis and interpretation of induced micro-seismicity by flooding of the Gardanne coal basin (Provence - Southern France). 77. EAGE Conference, Jun 2015, Madrid, Spain. ⟨ineris-01855048⟩