The Montello–Conegliano thrust is the most remarkable active tectonic structure of the Southern Alpine fault belt in the Veneto-Friuli plain, as a result of the conspicuous morphological evidence of the Montello anticline, which is associated to uplifted and deformed river terraces and diversion of the course of the Piave River.



The presence of several orders of Middle and Upper Pleistocene warped river terraces (Benedetti et al., 1999) in the western sector strongly suggests that the Montello-Conegliano anticline is active and driven by the underlying thrust.



However, despite the spectacular geomorphic and geologic evidence of activity of the Montello-Conegliano thrust, there is only little evidence on how much contractional strain is released through earthquakes and how much goes aseismic (Galadini et al., 2005).

Present-day seismicity The Conegliano-Montello sector of the Southern Alpine fold-and-thrust belt is characterized by a low seismicity level in the last 20 years, with respect to surrounding compartments (i.e., Lessini Mnts and Friuli). This observation may be interpreted in terms of 1) natural low seismicity rates or 2) instrumental bias due to the relatively scarce seismic network coverage in the area. In the first case, this may be related to the current state of fault coupling (indicating the presence of a mostly fully locked fault). In the second case thi may due to the presence of smaller magnitude earthquakes, undetectable with the seismic networks operating in this sector of Northern Italy.



Historical seismicity The Italian seismic catalogues have very poor-quality and incomplete data for the events associated with the Montello thrust, leaving room for different interpretations, as for example the possibility that these earthquakes were generated by nearby faults. In this latter case, the whole Montello–Conegliano thrust would represent a major “silent”, and locked, structure, because none of the historical earthquakes reported in the Italian Catalogues of seismicity for the past seven centuries can be convincingly referred to the Montello source. Alternatively, the Montello-Conegliano thrust may represent a creeping, or partially creeping, fault segment of the seismogenic Southern Alpine thrust front.



Global Positioning System (GPS) data are used to estimate velocities at the Earth's surface from the analysis of position time-series, and represents a fundamental tool for understanding the present day kinematics of Adia-Eurasia convergence, and for measuring present-day velocity gradients across the Southern Alpine fold-and-thrust belt. GPS data, and their recent interpretations (Battaglia et al., 2004; D'Agostino et al., 2005; Serpelloni et al., 2005; Weber et al., 2010), show that, at least for the Northern Adriatic region, crustal deformation are mainly driven by the 2-3 mm/a about North-South convergence of the Adria microplate with respect to the Eurasian plate. Relative Euler rotation poles of the two plates are located in the Western Alps.

During the last Civil Protection Department seismological projects (link), we started developing a kinematic model that accounts for both microplates relative motion and elastic strain accumulation at block-bounding faults. This preliminary model provides our kinematic framework for the enstablishment and realization of the GPS experiment across the Montello thrust fault.

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This regional scale kinematic model suggests that across the study region about 2 mm/a of N-S Adria-Eurasia convergence should be accommodated, with fault slip-rates of the order of 1 mm/a, on South verging thrust faults. In order to better understand how, and where, this plate convergence is accommodated across the Montello region, we developed a new GPS array.