Fault and basin depocentre migration over the last 2 Ma in the L'Aquila 2009 earthquake region, central Italian Apennines

摘要: Abstract Morphological, stratigraphical and structural investigations integrated with palaeomagnetic tephrostratigraphic studies 40 Ar/ 39 Ar measurements allowed us to define the Quaternary tectonic–sedimentary evolution of epicentral area L'Aquila 2009 earthquake (M w 6.3). This roughly matches Paganica–San Demetrio–Castelnuovo (PSC) intermountain basin filled by a fluvio-lacustrine succession that is variously deformed normal faults. At its early stage (Early Pleistocene; ca 2 Ma), hosted lake was characterised whitish carbonate silt mud deposition. Towards end Early Pleistocene, this partly south-eastward prograding deltaic system. The south-easternmost portion system successively abandoned eroded, while sedimentation braided river developed in smaller westwards. Before 780 ka, (the Lower PSC syntheme) ended, underwent erosional pedogenic processes. These processes continued up >460 ka, onset fluvial gravel volcanic-rich silty sand deposition over narrow south-western (an earlier unit Upper syntheme, Middle Pleistocene). Around 460 ka, when most again subjected denudational processes, migrated into previously exposed north-western basin, where fluvial/alluvial sediments were deposited, between 460 ka 350 ka (a later syntheme). Between present, uninterrupted slight westwards restricted (Upper–Late significant contraction shifting depocentre, variation geometry spatial distributions thicknesses units constituting Lower, Late synthemes, provide evidence for strong tectonic control. resulted progressive reduction activity structures parallel migration fault on westernmost structures. In perspective, responsible can be seen as recent expression long-lasting polarised process transfer.