Multidisciplinary analysis for unravelling physical and chemical signatures of tectonic deformation processes

The Upper Tiber Valley area presents a compelling seismotectonic setting, with many open questions to be investigated, along with an optimal scientific background and monitoring environment to study such topics with a broad perspective and a high level of detail. The complex seismotectonic setting of the Northern Apennines offers a unique and large combination of ingredients, all potentially showing key signatures of the earthquake’s nucleation and preparatory phases. Here there is a constant and high rate of microseismic release, evidence of fluids overpressure at depth, well- and mis-oriented normal faults (respect to the regional extensional stress field), marks of seismic and aseismic activity along them and a state-of-the-art multidisciplinary network monitoring all these components at high resolution in an area whose lithological distribution in 3D is very well constrained. Thus, here there is the potential to investigate a wide range of key topics in modern seismology and fault mechanics, by the integration of seismic with non-seismic data. That is why this thesis is based on the idea that the joint analysis of all this information can contribute to shed light on earthquake initiation and the mechanisms driving the recurrence and evolution of the seismic sequences. The main questions that I intend to investigate concern signals of various nature andform that can possibly be detected and traced back to tectonic and seismic processes, giving hints on the driving mechanisms. Are there detectable signals/anomalies linkable to seismic activity in the heterogeneous time series recorded by the multi- parametric instrumentation present in NFOs? If so, what are the relations with local earthquakes and between different datasets? How to compare the heterogeneous time series? And more: what is the role of crustal fluids in the seismic sequences of the area? Are there any identifiable seismic patterns that suggest such interactions? Do local earthquakes nucleate independently of lithology or are some layers more prone to trigger seismicity? These questions are addressed in the main chapters of the thesis, the structure of which is reported in the following.