Figure 1
From: Lithospheric double shear zone unveiled by microseismicity in a region of slow deformation
Seismotectonic sketch of eastern Central Italy in the Mediterranean framework. (a) Major thrust belts and distribution of P-axes of reverse/reverse-oblique earthquakes (M ≥ 3.0, depths < 40 km) occurred in the Mediterranean area in the time interval 1962–2016 (World Stress Map database5). (b) Kinematically homogeneous active deformation bands15 with P–T axes from a compilation of focal mechanisms (time interval 1968–2018, MW ≥ 3.5, depths < 40 km): A = upper crust extension, B = mid-crust extension, C = lower-crust contraction; D = upper-crust contraction, E = mid-to-lower crust strike-slip. Key: MAR = Mid Adriatic Ridge. (c) Quaternary and potentially seismogenic extensional and contractional structures and tectonic domains in eastern Central Italy. Historical and instrumental earthquakes from Parametric Catalogue of Italian Earthquakes, CPTI15 v4.026,30 and the Italian Seismological Instrumental and parametric Database ISIDe28 are also reported. The thick red lines represent the Adriatic Basal Thrust, and its major splay (Near Coast Thrust, NCT) analyzed in this paper; the thin red lines are the minor splays of ABT. The red labels represent the earthquakes cited in the text, and the yellow stars the major events that occurred in instrumental time; the numbers are related to the main seismic sequences of the study area. Key: 1 = Ancona 1972, MW 4.8; 2 = Porto San Giorgio 1987, MW 5.1; 3 = Faenza 2000, MW 4.9; 4 = Ancona 2013, MW 5.2.
