Young and tectonically active mountain chains like the Central Apennines (Italy) represent challenging areas where to investigate the relationship between fault development and seismotectonics. Those areas are fashioned by a very complex patterns of seismicity, which have been associated both to single fault or complex fault systems activation. The high structural complexity and repeated cycles of tectonic phases can be clearly recognized even from surface geology, especially when supported by highly detailed stratigraphic constraints. Nevertheless, the overprint of subsequent deformational stages must be taken into careful account since geological observations made at the surface might mask different structural architecture at depth, with consequent important implication for seismotectonics. The RETRACE-3D project focused on the review of a large set of underground data acquired for hydrocarbons explorations in the area struck by the 2016-2018 Central Apennines seismic sequence, integrated with surface geological information, to build a robust and comprehensive 3D geological model to be related to observed seismicity. Results primarily show that, at least for the shallow crust, the general architecture of the chain is still dominated by large-scale compressional structures associated to the build-up phase of the Central Apennines. We generally found widespread evidence of fault segmentation, reactivation of faults, as well as the recent generation of new sets of extensional faults. For these latter in particular, the surface expression and their evolution are conditioned by the presence of previous structures at depth. This contribution would open new points of discussion regarding a more realistic estimate of seismic hazard of complex areas such as the Central Apennines.
The impact of high structural complexity on seismotectonics: hints and lessons learned in the areas of the 2016-2018 central Italy seismic sequence in the framework of the RETRACE-3D project
Petracchini L;Scrocca D;Cavinato G;
2019
Abstract
Young and tectonically active mountain chains like the Central Apennines (Italy) represent challenging areas where to investigate the relationship between fault development and seismotectonics. Those areas are fashioned by a very complex patterns of seismicity, which have been associated both to single fault or complex fault systems activation. The high structural complexity and repeated cycles of tectonic phases can be clearly recognized even from surface geology, especially when supported by highly detailed stratigraphic constraints. Nevertheless, the overprint of subsequent deformational stages must be taken into careful account since geological observations made at the surface might mask different structural architecture at depth, with consequent important implication for seismotectonics. The RETRACE-3D project focused on the review of a large set of underground data acquired for hydrocarbons explorations in the area struck by the 2016-2018 Central Apennines seismic sequence, integrated with surface geological information, to build a robust and comprehensive 3D geological model to be related to observed seismicity. Results primarily show that, at least for the shallow crust, the general architecture of the chain is still dominated by large-scale compressional structures associated to the build-up phase of the Central Apennines. We generally found widespread evidence of fault segmentation, reactivation of faults, as well as the recent generation of new sets of extensional faults. For these latter in particular, the surface expression and their evolution are conditioned by the presence of previous structures at depth. This contribution would open new points of discussion regarding a more realistic estimate of seismic hazard of complex areas such as the Central Apennines.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
