[1] This interdisciplinary study on the subsurface stratigraphy of the Po Plain (northern Italy) brings new evidence in support of a climate-driven erosional unloading of the Alps since the Middle Pleistocene. A newly acquired, high-resolution seismic profile and a critical review of industrial seismic lines were integrated with sedimentologic observations on four magnetostratigraphically dated continental cores to reconstruct a three-sequence evolution of the Pleistocene clastic infill in the northern Po basin. During the first sequence (PS1; $1.4-0.87 Ma), characterized by sedimentation rates of $34 cm/kyr outpacing regional subsidence, meandering river systems prograded over the basin passing downstream to a cyclothemic shelfal succession. The second sequence (PS2; $0.87-0.45 Ma), heralded by a regional unconformity (R surface) correlated to the onset of the major Pleistocene glaciations, was characterized by widespread continental sedimentation of generally distal braidplain. The third sequence (PS3; $0.45 Ma to present), marked at the base by another regional unconformity (Y surface), is characterized by proximal braided fluvial deposition under combined conditions of confinement, erosion, and bypass. We interpret the PS3 sequence as deposited under the effects of a flexural uplift of the northern Po Plain during the Middle Pleistocene starting at $0.45 Ma, in response to the long-term erosional unloading of the Alps triggered by the waxing and waning of Alpine glaciers since the late Early Pleistocene global cooling ($0.9 Ma). According to our modeling, erosion on a relatively limited area of the Alpine mountain chain, ranging from 1.3 to 1.7 mm/yr in the axial sector to 0.1-0.3 mm/yr at the margins, has been able to trigger rock uplift over a wider area including the proximal peripheral basins.
Subsidence over the last 0.78 myr of a basin in central Italy bounded by a normal fault caused the deactivation and uplift of an Early–Middle Pleistocene alluvial fan at the fault footwall. Uplift of the fan occurred with a basin-bounding fault slip-rate of the order of 0.2 mm a
−1
. Subsidence resulted in the reorganization of the river network due to a fall in base level, which triggered headward erosion, stream piracy effects and drainage inversion. The mapped river inversions and catchment piracy were related to the distribution of a quantile regression of 134 alluvial fans v. basin areas. Despite the fact that the two parameters were well fitted by a power law relationship, all the fans corresponding to the captured rivers lay above the regression line (in the fan area field), whereas those corresponding to the capturing rivers were below the regression line (in the basin area field). We propose a general model of alluvial fan growth in active extensional settings that helps to interpret this scatter of fan v. basin area distribution and to identify the most active fault segments. Such an approach can better constrain fault activity in a time window that bridges long-term deformation and the present day deformation inferred from geodesy and/or seismology, increasing our understanding of the steadiness/unsteadiness behaviour of faults.
In August 2016, a magnitude 6.0 earthquake struck Central Italy, starting a devastating seismic sequence, aggravated by other two events of magnitude 5.9 and 6.5, respectively. After the first mainshock, four Italian institutions installed a dense temporary network of 50 seismic stations in an area of 260 km2. The network was registered in the International Federation of Digital Seismograph Networks with the code 3A and quoted with a Digital Object Identifier (10.13127/SD/ku7Xm12Yy9). Raw data were converted into the standard binary miniSEED format, and organized in a structured archive. Then, data quality and completeness were checked, and all the relevant information was used for creating the metadata volumes. Finally, the 99 Gb of continuous seismic data and metadata were uploaded into the INGV node of the European Integrated Data Archive repository. Their use was regulated by a Memorandum of Understanding between the institutions. After an embargo period, the data are now available for many different seismological studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.