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Dip. Sc. della Terra, Università di Napoli
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- PublicationRestrictedAnalysis of a 150 m sediment core from the co-seismic subsidence depocenter of the 2009 Mw=6.1 L'Aquila earthquake (Italy): Implications for Holocene-Pleistocene tectonic subsidence rates and for the age of the seismogenic Paganica fault system.(2016-09)
; ; ; ; ; ; ; ;Macrì, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Smedile, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Porreca, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Mochales, T.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Russo Ermolli, E.; Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, Università di Napoli Federico II; ; ; ; ; ; LAQUI-CORE was drilled in the co-seismic subsidence depocenter shown by DinSAR images in the Bazzano sub-basin after the 2009 Mw = 6.1 L'Aquila earthquake. LAQUI-CORE aimed at gathering high-resolution integrated stratigraphy and defining its relationships with the Paganica and other active faults that yielded co-seismic subsidence. Lithostratigraphy and micropaleontological analyses indicate a Late Pleistocene-Holocene fluvial-alluvial sequence, and below 41 m palustrine sediments sandwiching at 84–115 m a thick gravel package. Four 14C ages gathered from 5 to 15 m yield calibrated ages between 6 and 41 ka BP. Paleomagnetism reveals a normal polarity above 84 m, while below the gravel package (115 m) it shows frequent polarity changes. The occurrence of intervals of clear reverse polarity testifies below 115 m the deposition during the Matuyama Chron. We conclude that the normal polarity package, down to 84 m along with the underlying gravels, were deposited at high sedimentation rate (0.46 mm/yr for the upper 15 m) during the Brunhes Chron (< 0.78 Ma), and lie over a much older Early Pleistocene palustrine sequence that we correlate with the well-known Madonna della Strada Synthem (1.2–1.7 Ma). We assume that the subsidence driving the deposition of the upper normal polarity sequence was due to the activity of the Paganica and neighbour faults during the Middle-Late Pleistocene. The lack of thick volcanostratigraphic markers, widespread in colluvial sediments from the L'Aquila plain older than 460 ka, suggests a normal-polarity sedimentation onset, thus a Paganica fault activity onset, around 400 ka. The 0.25 to 0.50 mm/yr subsidence at Bazzano extrapolated by DinSAR data and paleoseismological trenching at the Paganica fault is roughly consistent with the sedimentation rate (0.46 mm/yr) yielded by radiocarbon dating in the upper LAQUI-CORE. This implies that co-seismic subsidence in the Bazzano sub-basin during Late Pleistocene-Holocene times was mainly controlled by the Paganica fault activity.515 28 - PublicationRestrictedEvolution of the late Quaternary San Gregorio Magno tectono-karstic basin (southern Italy) inferred from geomorphological, tephrostratigraphical and palaecological analyses: tectonic implications(2006)
; ; ; ; ; ; ; ;Aiello, G.; Dip. Sc. della Terra, Università di Napoli ;Ascione, A.; Dip. Sc. della Terra, Università di Napoli ;Barra, D.; Dip. Sc. della Terra, Università di Napoli ;Munno, R.; Dip. Sc. della Terra, Università di Napoli ;Petrosino, P.; Dip. Sc. della Terra, Università di Napoli ;Russo Ermolli, E.; Dip. Sc. della Terra, Università di Napoli ;Villani, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;; ; ; ; ; The Pantano di San Gregorio Magno is a 4.7 km 2 large tectono-karstic basin located in the axial belt of the Southern Apennines, an area affected by intense seismicity. The basin was formed in the Middle Pleistocene and is presently undissected. It is filled by lacustrine sediments (clays, silts and pyroclastic sands) passing laterally into alluvial fan deposits. Geomorphological investigations were integrated with tephrostratigraphical, palynological and palaeoecological analyses of a 61 m thick core (not reaching the bedrock). The multiproxy analysis of the S. Gregorio Magno record shows that, over the last 200k yr, the basin hosted a freshwater lake with an oscillating level. Age constraints provided by the tephrostratigraphic record allowed estimation of the sedimentation rate, which varied strongly through time. Evolution of the basin resulted from the complex combination of tectonic subsidence, karst processes and changing amounts of sedimentary inputs. The latter was influenced by allogenic contributions related both to primary and reworked volcanoclastic inputs and was climate-driven. The overall evidence, which indicates that in the long-term the accumulation rate substantially counterbalanced the accommodation space created by faulting, suggests that the basin evolution was also modulated by changing subsidence rates.222 28