Deep electrical resistivity tomography along the tectonically active Middle Aterno Valley (2009 L'Aquila earthquake area, central Italy)

摘要: Three 2-D Deep Electrical Resistivity Tomography (ERT) transects, up to 6.36 km long, were obtained across the Paganica-San Demetrio Basin, bounded by 2009 L'Aquila Mw 6.1 normal-faulting earthquake causative fault (central Italy). The investigations allowed defining for first time shallow subsurface basin structure. resistivity images, and their geological interpretation, show a dissected Mesozoic-Tertiary substratum buried under continental infill of mainly Quaternary age due long-term activity normal faults system (PSDFS), ruling most recent deformational phase. Our results indicate that bottom deepens 600 m moving south, with largely exceeding known thickness sequence. causes this increasing can be: (1) onset deposition in southern sector took place before Quaternary, (2) there was an early stage development driven different systems produced depocentre not related present-day shape, or (3) slip rate faster than northern sector. We able gain sights into PSDFS behaviour evolution, comparing throw rates at timescales discriminating splays lead deformation. Some exhibit large cumulative throws (>300 m) coincidence displacement deposits sequence (>100 m), thus testifying general persistence as leading system. evaluate (3–2.5 Myr) be 0.08–0.17 mm yr−1, indicating substantial stability activity. Among them, individual splay extends from Paganica San ne’ Vestini result post-Early Pleistocene linkage two smaller splays. This 15 long explain Holocene surface ruptures observed larger those occurred during earthquake, such revealed palaeoseismological investigations. Finally, architecture depth suggests also rupture longer structure surface, allowing earthquakes M 6.5, besides rupturing only small sections, it 2009.