Interpreting the interseismic deformation of the Altotiberina Fault (central Italy) through 2D modelling

• Main Authors: Debora Finocchio, Salvatore Barba, Stefano Santini, Antonella Megna
• Format: Article
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 2014-02-01
• Series: Annals of Geophysics
• Subjects: Low-angle normal faults; Earthquakes; Numerical model; Rheology
• Online Access: http://www.annalsofgeophysics.eu/index.php/annals/article/view/5806

The Altotiberina low-angle normal fault in central Italy has been a focus of many recent studies. Although the existence of this fault has long been known, its seismicity and relationship to other faults are still debated. We present a 2D elastoplastic finite-element model that reproduces the interseismic deformation of the Altotiberina Fault. The model predictions are compared to observed geodetic velocities, stress orientations and geological data. The influence of the Altotiberina Fault on interseismic evolution is tested by building several models with different boundary conditions. The best model is 180 km long, 40 km deep and contains two layers with different rheological parameters, two ramps, two faults and four freely slipping segments. The main factors contributing to the large-scale interseismic deformation include basal traction, rheology and the Altotiberina Fault itself, whereas the local, small-scale variations are due to two secondary high-angle faults.