World Stress Map Conference - International Lithosphere Program ...

Thursday, October 16 th
Poster Session VI: Stress field and interpretation at regional scale
Stress map of Italy update: new breakout data in southern
Apennines
Maria Teresa Mariucci, Paola Montone and Simona Pierdominici
Instituto Nazionale di Geofisica e Vulcanologia, Sezione Sismologia e Tettonofisica, Rome, Italy
mariucci@ingv.it
Here we present an updated stress map with a focus on southern Apennines. The Apennines
are a thrust and fold belt NE-verging characterized by a prevalent extensional tectonic regime.
Along the northern front of the belt, from the Po Plain to the Adriatic offshore, compression is
on the contrary still active, whereas in its southern part it seems stopped. Indeed, this area is
well known as one the most seismic zone in Italy, characterized by strong earthquakes in the
past that depict from the analysis of focal mechanisms an ongoing extensional tectonic regime
with T-axis about NE-SW. This is also evidenced by the active fault patterns, borehole
breakout data and geodetic data. Within this frame, the external area of the Apenninic belt, the
foredeep and the Apulian foreland, shows minor seismicity and a prevailing strike-slip
tectonics. New borehole breakouts were inferred from wells ranging from 1400 to 5500 depth
and are discussed in comparison to earthquake data and a few shallow stress regime
indicators. We analysed 45 new deep well data to better constrain the state of stress along the
Apenninic belt and foredeep. Some of these are located along the Val d’Agri basin showing a
prevalent NE-SW Shmin direction well consistent with the previous results. The most reliable
data confirmed the general trend of the southern Apennines but also new insights came out.
94 3 rd World Stress Map Conference, 15.-17. October 2008 in Potsdam