Lanzo G.,University of Rome La Sapienza |
Pagliaroli A.,CNR Institute of Environmental Geology and Geoengineering
Soil Dynamics and Earthquake Engineering | Year: 2012
An M w=6.3 earthquake originating at a normal fault in proximity of the city of L'Aquila produced a significant amount of near-fault strong-motion data recorded by an array deployed in the upper Aterno River Valley, NW of L'Aquila. This set of data deserves attention since it is the first well documented earthquake occurring in a near-fault area which was recorded from a moderate magnitude earthquake on a normal fault. For most of the stations geotechnical conditions are ascertained by means of drilling and geophysical investigation. To provide insights on the relevance of site conditions on measured near-source ground motions, peak and spectral values of acceleration and velocity recordings at stiff soil sites are compared with those at "rock" reference sites. Events of magnitude ranging between 3.0 and 6.3 (main event) were used. The results show that peak and response spectra values of ground motion, for the horizontal component and to a lesser extent for the vertical one, are affected by soil profile characteristics, especially for the station located on alluvium at the centre of the valley. For this station, observed amplification ratios were compared with numerical ones computed from 1D site response analyses. Evidence is presented that 1D numerical modelling is not able to completely explain the recorded motions. © 2012 Elsevier Ltd.
Palladino D.M.,University of Rome La Sapienza |
Sottili G.,CNR Institute of Environmental Geology and Geoengineering
Geophysical Research Letters | Year: 2012
Explosive volcanic activity on Earth is typically discontinuous in space and time. The occurrence of spatial/temporal eruption clusters due to mutual cause-and-effect relationships or external triggers (e.g., tectonic and/or tidal forcing) is still debated. To detect possible clustering of major explosive eruptions, we test the distribution of eruptions with Volcanic Explosivity Index (VEI) ≥ 4 from 1750 to present. The 143 documented VEI ≥ 4 events display a markedly non-uniform frequency distribution, with the highest relative probability of eruption recurrence within 500km distance from the preceding event. The analogous frequency pattern obtained from randomized data series of the same catalogue suggests that the observed eruption pattern is primarily imparted by the geodynamic distribution of volcanoes (mostly located along tectonically active linear belts), with no evidence of mutual or external influence. Our results highlight a counter-intuitive array of major eruption loci as a consequence of the intrinsic worldwide asymmetry of explosive volcanism, with implications on hazard assessment. © 2012. American Geophysical Union. All Rights Reserved.
Schildgen T.F.,University of Potsdam |
Yildirim C.,Technical University of Istanbul |
Cosentino D.,Third University of Rome |
Cosentino D.,CNR Institute of Environmental Geology and Geoengineering |
Strecker M.R.,University of Potsdam
Earth-Science Reviews | Year: 2014
The Central and Eastern Anatolian plateaus are integral parts of the world's third largest orogenic plateau. In the past decade, geophysical surveys have provided insights into the crust, lithosphere, and mantle beneath Eastern Anatolia. These observations are now accompanied by recent surveys in Central Anatolia and new data constraining the timing and magnitude of uplift along its northern and southern margins. Together with predictions from geodynamic models on the effects of various processes on surface deformation and uplift, the observations can be integrated to identify probable mechanisms of Anatolian Plateau growth.A changeover from shortening to extension along the southern margin of Central Anatolia that is coeval with the start of uplift can be most easily associated with oceanic slab break-off and tearing. This interpretation is supported by tomography, deep seismicity (or lack thereof), and gravity data. Based on the timing of uplift, geophysical and geochemical observations, and model predictions, slab break-off likely occurred first beneath Eastern Anatolia in middle to late Miocene time, and propagated westward toward Cyprus by the latest Miocene. Alternatively, the break-off near Cyprus could have occurred in late Pliocene to early Pleistocene time, in association with collision of the Eratosthenes Seamount (continental fragment) with the subduction zone. Uplift at the northern margin of Central Anatolia appears to result from crustal shortening starting in the late Miocene or early Pliocene, which has been linked to the broad restraining bend of the North Anatolian Fault. The uplift history of the interior of Central Anatolia since the late Miocene is unclear, although shortening there appears to have ended by the late Miocene, followed by NE-SW extension. This change in the deformation style broadly coincides with faster retreat of the Hellenic trench as well as uplift of the northern and southern margins of Central Anatolia.These different events throughout the plateau may be linked, as faster retreat of the Hellenic trench has been predicted to occur after slab break-off, which could have induced extension of Central Anatolia and helped to form the North Anatolian Fault through accelerated westward movement of Anatolia relative to Eurasia. Correlative geochronologic evidence that we summarize here supports the hypothesis that the geodynamic activity throughout the Aegean-Anatolian domain starting in latest Miocene to early Pliocene time defines a series of events that may all be linked to slab break-off. © 2013 Elsevier B.V.
Voltaggio M.,CNR Institute of Environmental Geology and Geoengineering
Radiation Protection Dosimetry | Year: 2012
During atmospheric thermal inversions, dew and hoarfrost concentrate gamma emitting radionuclides of the short-lived 222Rn progeny ( 214Pb and 214Bi), causing an increase in the total natural gamma background from the ground. To highlight this phenomenon, a volcanic zone of high 222Rn flux was studied during the winter season 2010-11. High-specific short-lived radon progeny activities up to 122 Bq g -1 were detected in hydrometeors forming at the earth's surface (ESHs), corresponding to a mean increase of up to 17 % of the normal gamma background value. A theoretical model, depending on radon flux from soil and predicting the radon progeny concentrations in hydrometeors forming at the ESHs is presented. The comparison between model and field data shows a good correspondence. Around nuclear power plants or in nuclear facilities that use automatic NaI or CsI total gamma spectroscopy systems for monitoring radioactive contamination, hydrometeors forming at the ESHs in sites with a high radon flux could represent a relevant source of false alarms of radioactive contamination. © The Author 2011. Published by Oxford University Press. All rights reserved.
Blengini G.A.,Polytechnic University of Turin |
Blengini G.A.,CNR Institute of Environmental Geology and Geoengineering |
Di Carlo T.,Polytechnic University of Turin
Energy and Buildings | Year: 2010
A detailed Life Cycle Assessment (LCA) has been conducted on a low energy family house recently built in Northern Italy. The yearly net winter heat requirement is 10 kWh/m2, while the same unit with legal standard insulation would require 110 kWh/m2. As the building was claimed to be sustainable on the basis of its outstanding energy saving performances, an ex post LCA was set up to understand whether, and to what extent, the positive judgement could be confirmed in a life cycle perspective. The dramatic contribution of materials-related impacts emerged. The shell-embedded materials represented the highest relative contribution, but maintenance operations also played a major role. The contributions of plants, building process and transportation were minor. The important role of the recycling potential also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles. The study has confirmed that the initial goal of environmental sustainability was reached, but to a much lower extent than previously thought. In comparison to a standard house, while the winter heat requirement was reduced by a ratio of 10:1, the life cycle energy was only reduced by 2.1:1 and the carbon footprint by 2.2:1. © 2010 Elsevier B.V. All rights reserved.
Carminati E.,CNR Institute of Environmental Geology and Geoengineering |
Doglioni C.,CNR Institute of Environmental Geology and Geoengineering
Earth-Science Reviews | Year: 2012
Alps and Apennines developed along opposite subductions, which inverted the tethyan passive continental margins located along the boundaries of Europe, Africa and the Adriatic plates. The Alps have higher morphological and structural elevation, two shallow, slow subsiding foreland basins. The Apennines have rather low morphological and structural elevation, one deep and fast subsiding foreland basin. While the Alps sandwiched the whole crust of both upper and lower plates, the Apennines rather developed by the accretion of the upper crust of the lower plate alone. Alpine relics are boudinated in the hangingwall of the Apennines, stretched by the Tyrrhenian backarc rifting. Relative to the upper plate, the subduction hinge moved toward it in the Alps from Cretaceous to Present, whereas it migrated away in the Apennines from late Eocene to Present, apart in Sicily where since Pleistocene(?) it reversed. The asymmetry appears primarily controlled by the slab polarity with respect to the westward drift of the lithosphere. © 2012 Elsevier B.V..
Ridente D.,CNR Institute of Environmental Geology and Geoengineering
Journal of the Geological Society | Year: 2016
Sequence stratigraphy arose as a paradigm in stratigraphy after the integration of the descriptive seismic method, introduced by Exxon researchers in the 1970s, with genetic concepts linking seismic attributes to sedimentary dynamics. Since then, the sequence stratigraphy model underwent significant modification owing to the increasing scenarios of application, each with its own practical requirements. This led to the fragmentation of the original model into a plethora of sub-methods and the flourishing of redundant notions and terminology. Reviewers striving to preserve the unity and fitness of sequence stratigraphy systematically weakened the central assumption by which it stood as a novelty and a paradigm: the relevance of relative sealevel cycles in shaping strata ‘sequentially’. In contrast to this attitude, the value of a model explicitly relying on the upholding control of sea-level is herein reconsidered, based on the marine record of Quaternary, climate-driven, sea-level cycles. Traditionally conceived as exceptionally short-lived and extraordinary events in the history of the Earth, these cycles are documented worldwide on modern continental margins, providing convincing evidence of how sea-level fluctuations actually shape sequences. © 2016, Journal of the Geological Society. All rights reserved.
Palombo M.R.,CNR Institute of Environmental Geology and Geoengineering
Quaternary International | Year: 2013
Mode and time of the first hominin diffusion in Eurasia, dispersal routes along geographical gradients, and factors promoting such dispersal are a hotly debated matter. Despite the growing amount of data, researchers are still far from deciphering the multifaceted relationships between climate changes and vegetation, fauna, and human evolutionary dynamics during the latest Cenozoic. A number of evidence suggests that it was not only climate, which shaped the evolutionary history of our own genus and affected hominin behaviour and dispersals, and that hominin movements cannot always be placed in the wider context of roughly contemporaneous changes of range of large mammalian taxa. In order to develop a more comprehensive understanding of the generality and underlying causal mechanisms for this complex scenario, a new, more integrated research agenda is recommended which requires the cultural and methodological support of disciplines of apparently remote, specialized sectors, such as geochemistry, sedimentology, geodynamics, palaeontology, palaeoecology, palaeonthropology, palinology, palaeobiology, and phylogeography. As all hypotheses about the environmental effects on evolution depend on temporal correlation, the central challenges should be: to finely resolve the chronological framework, to understand the nature of diachroneity among bioevents across geographical and ecological boundaries, to be able to make correlations between distant sequences, as well as to remove the sometimes confusing taxonomical treatments of some mammalian species, to improve understanding of the ecological settings where hominins evolved through advanced palaeoecological approaches (including both classic ecomorphological analysis and new biological and chemical techniques), and to provide high-resolution and integration of discontinuous climatic data, by developing a large, multidisciplinary database. © 2011 Elsevier Ltd and INQUA.
Lobo F.J.,University of Granada |
Ridente D.,CNR Institute of Environmental Geology and Geoengineering
Marine Geology | Year: 2014
This study is a review of Quaternary Milankovitch cycles as recorded on modern continental shelves worldwide. On the background of the many existing examples, we focus on selected case studies from Mediterranean (Adriatic and Tyrrhenian seas) and Atlantic (gulfs of Mexico and Cádiz) margins that represent general and peculiar characters of Middle-Upper Pleistocene sequences forming under the control of composite 100 and 20. ka Milankovitch cycles. The most pervasive stratigraphic pattern displayed by shelf deposits is referred to the 100. ka sea-level cycle, and consists of fairly uniform depositional sequences mostly composed by regressive deposits forming during the falling limb of the sea-level curve. These are generally classified as Falling Stage Systems Tract (FSST) and display a regressive facies architecture reflecting the dominant control of sea level. On many margins, FSST units may show slight though significant differences with respect to Highstand Systems Tract (HST) and Lowstand Systems Tract (LST) regressive units, more closely reflecting environmental changes and the local variability of depositional systems. In contrast with the theoretical and overall scale-independent model developed to predict composite stratigraphic cycles and sequences, the Middle-Upper Pleistocene stratigraphic record from numerous shelf settings shows a subdued signature of the higher-frequency (20. ka) Milankovitch cyclicity. However, when detectable, the 20. ka architectural pattern is characterized by a relatively greater spatial and temporal variability compared to 100. ka sequences. This fact likely reflects the increasing importance of factors controlling the depositional environment (e.g., seafloor morphology, oceanographic regime, sediment input and dispersal, etc) with respect to sea-level change during the shorter intervals encompassed by 20. ka. cycles. On this basis, two end-member cases have been distinguished, depending on the generation or not of high-frequency sequence boundaries, a prerequisite to qualify the higher-frequency motifs as depositional sequences. These two end members are comprehensive of the highly variable patterns displayed by Middle-Upper Pleistocene shelf sequences, which in turn reflect the interplay between the geological setting, the dominant sea-level control and the effective response of sedimentary systems. The variable stratigraphic patterns of Milankovitch cycles represent conceptual and practical constraints as to the classification of high-frequency Quaternary sequences under the general schemes of the standard sequence stratigraphy model. © 2013 Elsevier B.V.
Palombo M.R.,CNR Institute of Environmental Geology and Geoengineering
Quaternary International | Year: 2010
Throughout the Early to Middle Pleistocene several origination and extinction bioevents led to a progressive rebuilding of the structure of the Mediterranean mammalian communities. Understanding whether faunal dispersal and turnovers developed on a backdrop of climatic changes or intrinsic biotic factors exerted a more important control, it is an outstanding interest in elucidating the ecological scenario, enabling humans to disperse towards and across the Mediterranean region. Although a link between human dispersal and climate change possibly exists, many archaeologists continue to reject environmental determinism. The first dispersal of some human groups towards the Mediterranean was undoubtedly part of the Early Pleistocene faunal renewal triggered by climate changes, but the increase of suitable prey and limited competition with other predators would have been beneficial to human peopling.To contribute to the debate, the Early to Middle Pleistocene fossil record of large Mediterranean mammals has been analysed with the aim of delineating the main biological events and processes which affected the evolution of faunal complexes, in turn enabling humans to disperse throughout the Mediterranean region.The results of this study confirm that the most important renewals of large Mediterranean mammalian fauna (due to both originations/dispersals and extinctions) are connected to major global climatic changes that, via migrations and dispersal events, altered palaeocommunity equilibrium, leading to new intra- and inter-guild dynamics. Changes in the richness and crop biomass of principal prey, as in the relative abundance of forest and open environment dwellers, possibly had an important role in opening favourable windows to human dispersal during the late Early Pleistocene. Nonetheless, a significant peopling occurred only after the faunal renewal of the Early to Middle Pleistocene transition and at the time of functional turnovers throughout the beginning of the Middle Pleistocene. © 2009 Elsevier Ltd and INQUA.