GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 1.1 57 open the way to the application of this method for estimating patches of faults with same exposure time (paleo-seismology). Preliminary conclusions. Field-based SfM-MVS photogrammetry, and spectral surface analysis have been used to describe and investigate the roughness of fault surfaces recently exposed in the Monte Vettore area after the seismic sequence that hit Central Italy during 2016. Despite the preliminary nature of our investigation, results allowed us to provide the following key conclusions: • The field-based Structure from Motion-MultiView Stereo (SfM-MVS) photogrammetry provides high quality data of the fault surface topography adapted to rough terrain conditions. • Fracture roughness varies along dip in terms of wavelength and amplitude, likely indicating an interplay of different processes, such as wearing and weathering. • Fault roughness is slightly anisotropic due to the presence of smooth and wide undulations (slip indicators). References Candela, T., Renard, F., Bouchon, M., Brouste, A., Marsan, D., Schmittbuhl, J., and Voisin, C. ; 2009: Characterization of fault roughness at various scales: Implications of three-dimensional high resolution topography measurements. In Mechanics, structure and evolution of fault zones  (pp. 1817-1851). Birkhäuser Basel. Candela, T., Renard, F., Klinger, Y., Mair, K., Schmittbuhl, J., and Brodsky, E. E.; 2012: Roughness of fault surfaces over nine decades of length scales . Journal of Geophysical Research: Solid Earth, 117(B8). Corradetti, A., McCaffrey, K.J.W., De Paola, N. and Tavani, S.; 2017: Evaluating roughness scaling properties of natural active fault surfaces by means of multi-view photogrammetry . Tectonophysics 717, 599–606. Corradetti, A., Tavani, S., Parente, M., Iannace, A., Vinci, F., Pirmez, C., Torrieri, S., Giorgioni, M., Pignalosa, A., Mazzoli, S.; 2018: Distribution and arrest of vertical through-going joints in a seismic-scale carbonate platform exposure (Sorrento peninsula, Italy): insights from integrating field survey and digital outcrop model . J. Struct. Geol. 108, 121–136. https://doi.org/10.1016/j.jsg.2017.09.009 Fig. 3 - Detailed analysis of fracture roughness variation along the slip. Both parameters controlling the Power Spectral Density, Hurst exponent (H) and pre-factor (a) are varying along the slip.