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Voltaggio, M.
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Voltaggio, M.
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- PublicationOpen AccessTephra layers from Holocene lake sediments of the Sulmona Basin,(2009-12)
; ; ; ; ; ; ; ; ;Giaccio, B.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Area della Ricerca RM1-Montelibretti, ;Messina, P.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Area della Ricerca RM1-Montelibretti, ;Sposato, A.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Area della Ricerca RM1-Montelibretti, ;Voltaggio, M.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Area della Ricerca RM1-Montelibretti, ;Zanchetta, G.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy ;Galadini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Gori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Santacroce, R.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy; ; ; ; ; ; ; We present a new tephrostratigraphic record from the Holocene lake sediments of the Sulmona basin, central Italy. The Holocene succession is represented by whitish calcareous mud that is divided into two units, SUL2 (ca 32 m thick) and SUL1 (ca 8 m thick), for a total thickness of ca 40 m. These units correspond to the youngest two out of six sedimentary cycles recognised in the Sulmona basin that are related to the lake sedimentation since the Middle Pleistocene. Height concordant U series age determinations and additional chronological data constrain the whole Holocene succession to between ca 8000 and 1000 yrs BP. This includes a sedimentary hiatus that separates the SUL2 and SUL1 units, which is roughly dated between <2800 and ca 2000 yrs BP. A total of 31 and 6 tephra layers were identified within the SUL2 and SUL1 units, respectively. However, only 28 tephra layers yielded fresh micropumices or glass shards suitable for chemical analyses using a microprobe wavelength dispersive spectrometer. Chronological and compositional constraints suggest that 27 ash layers probably derive from the Mt. Somma-Vesuvius Holocene volcanic activity, and one to the Ischia Island eruption of the Cannavale tephra (2920 _ 450 cal yrs BP). The 27 ash layers compatible with Mt. Somma-Vesuvius activity are clustered in three different time intervals: from ca 2000 to >1000; from 3600 to 3100; and from 7600 to 4700 yrs BP. The first, youngest cluster, comprises six layers and correlates with the intense explosive activity of Mt. Somma-Vesuvius that occurred after the prominent AD 79 Pompeii eruption, but only the near-Plinian event of AD 472 has been tentatively recognised. The intermediate cluster (3600– 3100 yrs BP) starts with tephra that chemically and chronologically matches the products from the ‘‘Pomici di Avellino’’ eruption (ca 3800_ 200 yrs BP). This is followed by eight further layers, where the glasses exhibit chemical features that are similar in composition to the products from the so-called ‘‘Protohistoric’’ or AP eruptions; however, only the distal equivalents of three AP events (AP3, AP4 and AP6) are tentatively designated. Finally, the early cluster (7600–4700 yrs BP) comprises 12 layers that contain evidence of a surprising, previously unrecognised, activity of the Mt. Somma-Vesuvius volcano during its supposed period of quiescence, between the major Plinian ‘‘Pomici di Mercato’’ (ca 9000 yrs BP) and ‘‘Pomici di Avellino’’ eruptions. Alternatively, since at present there is no evidence of a similar significant activity in the proximal area of this well-known volcano, a hitherto unknown origin of these tephras cannot be role out. The results of the present study provide new data that enrich our previous knowledge of the Holocene tephrostratigraphy and tephrochronology in central Italy, and a new model for the recent explosive activity of the Peninsular Italy volcanoes and the dispersal of the related pyroclastic deposits.249 414 - PublicationRestrictedRevised Chronology of the Sulmona Lacustrine Succession, Central Italy(2013-08)
; ; ; ; ; ; ;Giaccio, B.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Monterotondo, Rome, Italy ;Castorina, F.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Monterotondo, Rome, Italy ;Nomade, S.; Laboratoire des Sciences du Climat et de l’Environnement, IPSL, laboratoire CEA/CNRS/UVSQ, Gif-Sur-Yvette, France ;Scardia, G.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Monterotondo, Rome, Italy ;Voltaggio, M.; Istituto di Geologia Ambientale e Geoingegneria, CNR, Monterotondo, Rome, Italy ;Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; We present new stratigraphic, palaeomagnetic, 87Sr/86Sr and 40Ar/39Ar data from a lacustrine succession of the Sulmona basin, central Italy, which, according to an early study, included six unconformitybounded lacustrine units (from SUL6, oldest, to SUL1, youngest) spanning the interval >600 to 2 ka. The results of the present study, on the one hand confirm some of the previous conclusions, but by contrast reveal that units SUL2 and SUL1, previously attributed to the Holocene, are actually equivalent to the older SUL6 and SUL5 units – here dated to 814–>530 ka and 530–<457 ka, respectively – and that the U-series dates previously published for both former SUL2 and SUL1 units yielded abnormally young ages. In light of the present results, a reassessment of the chronology of the Sulmona basin succession and a revision of the tephrostratigraphy of the SUL2/SUL6 and SUL1/SUL5 units is in order.195 33 - PublicationRestrictedGeographically weighted regression and geostatistical techniques to construct the geogenic radon potential map of the Lazio region: A methodological proposal for the European Atlas of Natural Radiation(2017-01)
; ; ; ; ; ; ; ; ; ; ; ; ;In many countries, assessment programmes are carried out to identify areas where people may be exposed to high radon levels. These programmes often involve detailed mapping, followed by spatial interpolation and extrapolation of the results based on the correlation of indoor radon values with other parameters (e.g., lithology, permeability and airborne total gamma radiation) to optimise the radon hazard maps at the municipal and/or regional scale. In the present work, Geographical Weighted Regression and geostatistics are used to estimate the Geogenic Radon Potential (GRP) of the Lazio Region, assuming that the radon risk only depends on the geological and environmental characteristics of the study area. A wide geodatabase has been organised including about 8000 samples of soil-gas radon, as well as other proxy variables, such as radium and uranium content of homogeneous geological units, rock permeability, and faults and topography often associated with radon production/migration in the shallow environment. All these data have been processed in a Geographic Information System (GIS) using geospatial analysis and geostatistics to produce base thematic maps in a 1000 m × 1000 m grid format. Global Ordinary Least Squared (OLS) regression and local Geographical Weighted Regression (GWR) have been applied and compared assuming that the relationships between radon activities and the environmental variables are not spatially stationary, but vary locally according to the GRP. The spatial regression model has been elaborated considering soil-gas radon concentrations as the response variable and developing proxy variables as predictors through the use of a training dataset. Then a validation procedure was used to predict soil-gas radon values using a test dataset. Finally, the predicted values were interpolated using the kriging algorithm to obtain the GRP map of the Lazio region. The map shows some high GRP areas corresponding to the volcanic terrains (central-northern sector of Lazio region) and to faulted and fractured carbonate rocks (central-southern and eastern sectors of the Lazio region). This typical local variability of autocorrelated phenomena can only be taken into account by using local methods for spatial data analysis. The constructed GRP map can be a useful tool to implement radon policies at both the national and local levels, providing critical data for land use and planning purposes.111 3 - PublicationOpen AccessThe Paganica Fault and surface coseismic ruptures caused by the 6 april 2009 earthquake (L’Aquila, central Italy)(2009-11)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Falcucci, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Gori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Peronace, E.; Dipartimento della Protezione Civile ;Fubelli, G.; Università di Roma 3 ;Moro, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Saroli, M.; Università di Cassino ;Giaccio, B.; CNR-IGAG ;Messina, P.; CNR-IGAG ;Naso, G.; Dipartimento della Protezione Civile ;Scardia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Sposato, A.; CNR-IGAG ;Voltaggio, M.; CNR-IGAG ;Galli, P.; Dipartimento della Protezione Civile ;Galadini, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; ; ; ; ; ; ; ; ; ; ; ; ; On 6 April 2009, at 01:32 GMT, an Mw 6.3 seismic event hit the central Apennines, severely damaging the town of L’Aquila and dozens of neighboring villages and resulting in approximately 300 casualties (Istituto Nazionale di Geofisica e Vulcanologia, http://www.ingv.it; MedNet, http://mednet.rm.ingv.it/proce- dure/events/QRCMT/090406_013322/qrcmt.html). This earth- quake was the strongest in central Italy since the devastating 1915 Fucino event (Mw 7.0). The INGV national seismic net- work located the hypocenter 5 km southwest of L’Aquila, 8–9 km deep. Based on this information and on the seismotectonic framework of the region, earthquake geologists traveled to the field to identify possible surface faulting (Emergeo Working Group 2009a, 2009b). The most convincing evidence of pri- mary surface rupture is along the Paganica fault, the geometry of which is consistent with seismological, synthetic aperture radar (SAR) and GPS data. Investigation of other known nor- mal faults of the area, i.e., the Mt. Pettino, Mt. San Franco, and Mt. Stabiata normal faults suggested that these structures were not activated during the April 6 shock (Emergeo Working Group 2009a, 2009b). In this report, we first describe the seismotectonic frame- work of the area, and then we present the field information that supports the occurrence of surficial displacement on the Paganica fault.270 417 - PublicationRestrictedJanuary 2002 volcano-tectonic eruption of Nyiragongo volcano, Democratic Republic of Congo(2007-09-18)
; ; ; ; ; ; ; ; ; ;Tedesco, D.; Department of Environmental Sciences, Second University of Naples, Caserta, Italy - Institute of Environmental Geology and Geo-Engineering, Consiglio Nazionale delle Ricerche, Rome, Italy ;Vaselli, O.; Department of Earth Sciences, University of Florence, Florence, Italy - Institute of Geosciences and Earth Resources, Consiglio Nazionale delle Ricerche, Florence, Italy ;Papale, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Carn, S. A.; Joint Center for Earth Systems Technology, University of Maryland Baltimore County, Baltimore, Maryland, USA ;Voltaggio, M.; Institute of Environmental Geology and Geo-Engineering, Consiglio Nazionale delle Ricerche, Rome, Italy ;Sawyer, G. M.; Department of Geography, University of Cambridge, Cambridge, UK ;Durieux, J.; Goma Volcano Observatory, Mount Goma, Goma, Democratic Republic of Congo ;Kasereka, M.; Goma Volcano Observatory, Mount Goma, Goma, Democratic Republic of Congo ;Tassi, F.; Department of Earth Sciences, University of Florence, Florence, Italy; ; ; ; ; ; ; ; In January 2002, Nyiragongo volcano erupted 14–34 × 106 m3 of lava from fractures on its southern flanks. The nearby city of Goma was inundated by two lava flows, which caused substantial socioeconomic disruption and forced the mass exodus of the population, leaving nearly 120,000 people homeless. Field observations showed marked differences between the lava erupted from the northern portion of the fracture system and that later erupted from the southern part. These observations are confirmed by new 238U and 232Th series radioactive disequilibria data, which show the presence of three different phases during the eruption. The lavas first erupted (T1) were probably supplied by a residual magma batch from the lava lake activity during 1994–1995. These lavas were followed by a fresh batch erupted from fissure vents as well as later (May–June 2002) from the central crater (T2). Both lava batches reached the surface via the volcano's central plumbing system, even though a separate flank reservoir may also have been involved in addition to the main reservoir. The final phase (T3) is related to an independent magmatic reservoir located much closer (or even beneath) the city of Goma. Data from the January 2002 eruption, and for similar activity in January 1977, suggest that the eruptive style of the volcano is likely to change in the future, trending toward more common occurrence of flank eruptions. If so, this would pose a significant escalation of volcanic hazards facing Goma and environs, thus requiring the implementation of different volcano-monitoring strategies to better anticipate where and when future eruptions might take place.310 27