GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.1 GNGTS 2023 connected to the PF at depth, such as synthetic and antithetic splays. As the rupturing occurs along a pre-existing fault, rank 1.5 DRs are usually more continuous and have larger displacement than rank 2 DRs. Faults reactivated as rank 1.5 DRs may or may not be able to provoke an earthquake by themselves. They may provoke rank 2 DRs of their own. Rank 1.5 DRs are identified in earthquakes of all kinematics. Rank 3 is triggered distributed rupturing along pre-existing faults that are not likely to be connected to the PF, generally at far distance from the PF. Typically, rank 3 DRs are highly discontinuous along and around the pre-existing fault trace. Triggered DRs are hosted by active faults, but the level of their own activity may vary. Rank 3 rupturing can be triggered along faults that can act as PF during a different earthquake. Rank 3 DRs can be present in any fault kinematics. Rank 21 (Bending-moment, B-M) and rank 22 (flexural-slip, F-S) are DRs occurring during reverse faulting earthquakes, when large-scale folding may lead bending-moment or flexural-slip rupturing. B-M DRs are normal faults that are formed close to the hinge zone of large-scale anticlines. F-S DRs are due to slip along bedding planes on steeply-dipping limbs of a bedrock fold.