Three-dimensional characterization of a crustal-scale fault zone: the Pusteria and Sprechenstein fault system (Eastern Alps)

@inproceedings{BistacchiRM2008,
 abstract = { The characterization and representation of fault zones is of paramount importance for fault and earthquake mechanics studies since their rheological and geometric complexity controls the seismic/aseismic behaviour and fluid circulation at depth. In this work a 3D geological model of a fault network realized by integrating borehole data and detailed 1:5000 geological mapping is presented. The model allows (i) fault zone architecture, including fault network geometry and topology, (ii) fault rock distribution, and (iii) degree of damage to be quantitatively or semi-quantitatively evaluated at the kmscale. For the latter purpose, we have introduced and validated an ad hoc classification called Damage Index. The modelled fault network is located in the Eastern Italian Alps, where the Pusteria Fault (a segment of the major fault system of the Alps – the Periadriatic Lineament) is displaced dextrally by the Sprechenstein-Mules Fault. This fault network, complicated by contractional step-overs, provides the opportunity to study fault rocks and damage distribution as a function of fault geometry and host-rock lithology, as three distinct protoliths are involved in faulting: foliated tonalites, (mylonitic) paragneiss and massive granitoids. A first-order influence on fault rocks and damage distribution is exerted by the composition and inherited fabric of protoliths, resulting in a marked asymmetry of damage zones when different tectonic units are juxtaposed across a fault segment. In addition also the presence of step-overs has a strong influence on damage distribution. To conclude, the approach adopted for the 3D reconstruction of the Pusteria and Sprechenstein-Mules fault zone architecture resulted particularly suitable to bridge the gap between classical outcrop-scale descriptions and large-scale geophysical models. },
 author = { Bistacchi, Andrea AND Massironi, Matteo AND Menegon, Luca },
 booktitle = { 28th gOcad Meeting },
 month = { "june" },
 publisher = { ASGA },
 title = { Three-dimensional characterization of a crustal-scale fault zone: the Pusteria and Sprechenstein fault system (Eastern Alps) },
 year = { 2008 }
}