Insights into the Paleostress Analysis of Heterogeneous Fault-Slip Data by Comparing Different Methodologies: The Case of the Voltri Massif in the Ligurian Alps (NW Italy)

One of the most critical stages in fault-slip data stress analysis is separating fault into homogeneous subsets and selecting a suitable method for each subset. A basic assumption tensor computations that activations occur simultaneously under regime. With rationale, this work aims to attain improvements paleostress reconstruction from polyphase deformed region Voltri Massif Ligurian Alps by using already published heterogeneous inverted best-fit inversion methods absence any tectonostratigraphic overprinting criteria. The are re-examined analyzed with Tensor Ratio Method (TRM) This defines crucial differences history Alps, gives insight results different methodologies. Best-fit site tensors have substantial diversity orientations ratios, implying possible perturbations region. reason these diversities Misfit Angle (MA) minimization criterion taken account allows acceptable combinations, which additional geological compatibility criteria used TRM, found be incompatible. TRM application on similar bulk fewer ratios defined whose always satisfy same induced not only MA criterion. Thus, seems define as sensitive input data, compared appear suffer ‘overfitting’ modeling error. Five distinct provide more constrained after restoration ~50° CCW rotation, comprise: (a) transpression–strike-slip regime (T1) NNE-SSW contraction Late Eocene, (b) an Oligocene NW-SE extensional (T2), fits extension documented broader area north Corsica due significant change subduction dynamics, (c) transient, local, or ephemeral NE-SW transtension (T3) might considered local mutual permutation T2 stresses, (d) Miocene transpression progressively shifted ENE-WSW (T4) (T5), reflecting reorganization decrease retreating rate northern Apennines slab. Therefore, can fairly described enhanced Andersonian tensors, requires than sophisticated tools faulting events.