State of stress in southern Italy from borehole breakout and focal mechanism data

摘要: We present new wellbore breakout data from oil exploration wells drilled in southern Peninsular Italy, the Tyrrhenian shelf through Apenninic mountain belt and foredeep, eastward to undeformed Adria foreland. From analysis of 64 wells, we observe S hmin oriented around NE-SW, perpendicular trend Apennines, both within eastern foredeep. Some variations are observed few analyzed on shelf, possibly due local tectonic structures, such as transverse NE-SW extensional basins. The Apulian platform overthrust by mountains at 3-4 km depth, shows a very consistent direction N40°-50°E, agreement with stress regime inferred focal mechanisms strong earthquakes depths 10-15 km, which show NE extension, mostly accomplished normal faulting. overlying sedimentary allochthonous units exhibit same direction, but larger scatter. Breakout demonstrate that Quaternary compressional tectonism has ended, is also foreland far 50 seismic belt. In easternmost sector there suggestions nearly isotropic horizontal field, most do not significant ellipticity.