Pore pressure pulse drove the 2012 Emilia (Italy) series of earthquakes

Induced seismicity has increasingly become a major topic among earth scientist. Concerns about a causative role played by the oil-gas extraction and/or the deep The 2012 Emilia earthquakes sequence is the first debated case in Italy of destructive event possibly induced by anthropic activity. During this sequence, two main earthquakes occurred separated by nine days on contiguous thrust faults. Scientific commissions engaged by the Italian government reported complementary scenarios on the potential trigger mechanism ascribable to exploitation of a nearby oil field. In this study, we combine a refined geodetic source model constrained by precise aftershock locations and an improved tomographic model of the area to define the geometrical relation between the activated faults and investigate possible triggering mechanisms. An aftershocks decay rate that deviates from the classical Omori-like pattern and Vp/Vs changes along the fault system suggests that pore pressure pulse drove the space-time evolution of seismicity and the activation of the second mainshock.