http://hdl.handle.net/2122/234 2013-05-25T00:09:04Z http://hdl.handle.net/2122/8683 Title: Repeat-station surveys: implications from chaos and ergodicity of the recent geomagnetic field Authors: De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The present geomagnetic field is chaotic and ergodic: chaotic because it can no longer be predicted beyond around 6 years; and ergodic in the sense that time averages correspond to phase-space averages. These properties have already been deduced from complex analyses of observatory time series in a reconstructed phase space [Barraclough and De Santis 1997] and from global predicted and definitive models of differences in the time domain [De Santis et al. 2011]. These results imply that there is a strong necessity to make repeat-station magnetic surveys more frequently than every 5 years. This, in turn, will also improve the geomagnetic field secular variation models. This report provides practical examples and case studies. 2013-04-17T22:00:00Z http://hdl.handle.net/2122/8620 Title: Italian Magnetic Network and Geomagnetic Field Maps of Italy at year 2010.0 Authors: Dominici, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Sperti, M.; Istituto Geografico Militare, Firenze; Manzo, G.; Istituto Geografico Militare, Firenze; Maseroli, R.; Istituto Geografico Militare, Firenze Abstract: In the frame of a long-time collaboration between INGV (Istituto Nazionale di Geofisica e Vulcanologia) and IGMI (Istituto Geografico Militare Italiano), also in the years 2009 and 2010 a survey of 131 repeat stations of the Italian Magnetic Network (including 2 observatories, 11 stations in Albania and 3 in Corsica and 1 in Malta) was carried out. In this paper the procedures for magnetic measurements and data elaboration are described. Furthermore, for all the repeat stations data reduced at of the measurement day, at the epoch 2010.0; are presented. At the same epoch the coefficients for normal fields were determined for all the data, in order to draw the new maps of the geomagnetic field elements (D, H, Z and total field F) at the year 2010.0, at 1: 2 000 000 scale. All these maps were created by mean of interpolation procedures on GIS platform. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8591 Title: Italian Magnetic Network and magnetic reference fields at 2010.0 Authors: Dominici, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Di Ponzio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Miconi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has systematically undertaken the task of making measurements of the Earth's magnetic field in Italy. By tradition and because of the elongated geometric shape of our peninsula and islands, in Italy, a grid of more than 110 points, called the first order repeat stations, with an average spacing around 55-60 km, is in operation. Over this grid the measurements are repeated regularly, every 5 years. A survey of 131 repeat stations of the Italian Magnetic Network (including 2 observatories, 11 stations in Albania, 3 stations in Corsica and 1 in Malta) was carried out between 2009 and 2010 with the main purpose of updating our magnetic cartography. We describe the characteristics of magnetic first and second order networks, the magnetic measurements and the data reduction procedure. In agreement with the recommendations of MagNetE Committee, we report new repeat station data measured and reduced at 2010.0. An analytical expression, a second order polynomial, in latitude and longitude for the field elements, was determined, and coefficients for 2010.0 and average secular variation over the period 2005-2010, were obtained. The new maps for Italy, for D, F, H and Z at the epoch 2010.0, are shown. A selection of stations from the Italian Magnetic Network, based on their low values of anomaly with respect to a 'normal' field, is also proposed for future surveys. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8473 Title: Geomagnetic South Atlantic Anomaly and global sea level rise: A direct Connection? Authors: De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Spada, G.; Dipartimento di Scienze di Base e Fondamenti, Urbino University ‘‘CarloBo’’, Urbino, Italy; Gasperini, P.; Dipartimento di Fisica, Settore Geofisica, Università di Bologna, Bologna, Italy Abstract: We highlight the existence of an intriguing and to date unreported relationship between the surface area of the South Atlantic Anomaly (SAA) of the geomagnetic field and the current trend in global sea level rise. These two geophysical variables have been growing coherently during the last three centuries, thus strongly suggesting a causal relationship supported by some statistical tests. The monotonic increase of the SAA surface area since 1600 may have been associated with an increased inflow of radiation energy through the inner Van Allen belt with a consequent warming of the Earth’s atmosphere and finally global sea level rise. An alternative suggestive and original explanation is also offered, in which pressure changes at the core–mantle boundary cause surface deformations and relative sea level variations. Although we cannot establish a clear connection between SAA dynamics and global warming, the strong correlation between the former and global sea level supports the idea that global warming may be at least partly controlled by deep Earth processes triggering geomagnetic phenomena, such as the South Atlantic Anomaly, on a century time scale. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/7176 Title: A Holocene paleosecular variation record from the northwestern Barents Sea continental margin Authors: Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Macrì, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Lucchi, R.; Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Borgo Grotta Gigante 42/c, Sgonico, Trieste I‐34010, Italy; Rebesco, M.; Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Borgo Grotta Gigante 42/c, Sgonico, Trieste I‐34010, Italy; Camerlenghi, A.; Istitució Catalana de Recerca i Estudis Avançats, E‐08028 Barcelona, Spain Abstract: A high‐resolution paleomagnetic and rock magnetic study has been carried out on sediment cores collected in glaciomarine silty‐clay sequences from the continental shelf and slope of the southern Storfjorden trough‐mouth fan, on the northwestern Barents Sea continental margin. The Storfjorden sedimentary system was investigated during the SVAIS and EGLACOM cruises, when 10 gravity cores, with a variable length from 1.03 m to 6.41 m, were retrieved. Accelerator mass spectrometry (AMS) 14C analyses on 24 samples indicate that the cores span a time interval that includes the Holocene, the last deglaciation phase and in some cores the last glacial maximum. The sediments carry a well‐defined characteristic remanent magnetization and have a valuable potential to reconstruct the paleosecular variation (PSV) of the geomagnetic field, including relative paleointensity (RPI) variations. The paleomagnetic data allow reconstruction of past dynamics and amplitude of the geomagnetic field variations at high northern latitudes (75°–76° N). At the same time, the rock magnetic and paleomagnetic data allow a high‐resolution correlation of the sedimentary sequences and a refinement of their preliminary age models. The Holocene PSV and RPI records appear particularly sound, since they are consistent between cores and they can be correlated to the closest regional stacking curves (UK PSV, FENNOSTACK and FENNORPIS) and global geomagnetic model for the last 7 ka (CALS7k.2). The computed amplitude of secular variation is lower than that outlined by some geomagnetic field models, suggesting that it has been almost independent from latitude during the Holocene. 2011-10-31T23:00:00Z http://hdl.handle.net/2122/7104 Title: Societal need for improved understanding of climate change, anthropogenic impacts, and geo-hazard warning drive development of ocean observatories in European Seas Authors: Ruhl, H. A.; NOCS; Andrè, M.; UPC; Beranzoli, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Çagatay, M. N.; ITU; Colaço, A.; Univ. Azores; Cannat, M.; IPGP; Dañobeitia, J. J.; CSIC-UTM; Favali, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Géli, L.; IFREMER; Gillooly, M.; IMI; Greinert, J.; NIOZ; Hall, P. O. J.; Univ. Goteborg; Huber, R.; MARUM; Karstensen, J.; Univ. Kiel; Lampitt, R. S.; NOCS; Larkin, K. E.; NOCS; Lykousis, V.; HCMR; Mienert, J.; Univ. Tromsø; Miranda, J. M.; Univ. Lisboa; Person, R.; IFREMER; Priede, I. G.; Univ. Aberdeen; Puillat, I.; IFREMER; Thomsen, L.; Jacobs Univ. Bremen; Waldmann, C.; MARUM Abstract: Society’s needs for a network of in situ ocean observing systems cross many areas of earth and marine science. Here we review the science themes that benefit from data supplied from ocean observatories. Understanding from existing studies is fragmented to the extent that it lacks the coherent long-term monitoring needed to address questions at the scales essential to understand climate change and improve geo-hazard early warning. Data sets from the deep sea are particularly rare with long-term data available from only a few locations worldwide. These science areas have impacts on societal health and well-being and our awareness of ocean function in a shifting climate. Substantial efforts are underway to realise a network of open-ocean observatories around European Seas that will operate over multiple decades. Some systems are already collecting high-resolution data from surface, water column, seafloor, and sub-seafloor sensors linked to shore by satellite or cable connection in real or near-real time, along with samples and other data collected in a delayed mode. We expect that such observatories will contribute to answering major ocean science questions including: How can monitoring of factors such as seismic activity, pore fluid chemistry and pressure, and gas hydrate stability improve seismic, slope failure, and tsunami warning? What aspects of physical oceanography, biogeochemical cycling, and ecosystems will be most sensitive to climatic and anthropogenic change? What are natural versus anthropogenic changes? Most fundamentally, how are marine processes that occur at differing scales related? The development of ocean observatories provides a substantial opportunity for ocean science to evolve in Europe. Here we also describe some basic attributes of network design. Observatory networks provide the means to coordinate and integrate the collection of standardised data capable of bridging measurement scales across a dispersed area in European Seas adding needed certainty to estimates of future oceanic conditions. Observatory data can be analysed along with other data such as those from satellites, drifting floats, autonomous underwater vehicles, model analysis, and the known distribution and abundances of marine fauna in order to address some of the questions posed above. Standardised methods for information management are also becoming established to ensure better accessibility and traceability of these data sets and ultimately to increase their use for societal benefit. The connection of ocean observatory effort into larger frameworks including the Global Earth Observation System of Systems (GEOSS) and the Global Monitoring of Environment and Security (GMES) is integral to its success. It is in a greater integrated framework that the full potential of the component systems will be realised. 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7035 Title: Ergodicity of the recent geomagnetic field Authors: De Santis, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Qamili, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cianchini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The geomagnetic field is a fundamental property of our planet: its study would allow us to understand those processes of Earth’s interior, which act in its outer core and produce the main field. Knowledge of whether the field is ergodic, i.e. whether time averages correspond to phase space averages, is an important question since, if this were true, it would point out a strong spatio-temporal coupling amongst the components of the dynamical system behind the present geomagnetic field generation. Another consequence would be that many computations, usually undertaken with many difficulties in the phase space, can be made in the conventional time domain. We analyse the temporal behaviour of the deviation between predictive and definitive geomagnetic global models for successive intervals from 1965 to 2010, finding a similar exponential growth with time. Also going back in time (at around 1600 and 1900 by using the GUFM1 model) confirms the same findings. This result corroborates previous chaotic analyses made in a reconstructed phase space from geomagnetic observatory time series, confirming the chaotic character of the recent geomagnetic field with no reliable prediction after around 6 years from definitive values, and disclosing the potentiality of estimating important entropic quantities of the field by time averages. Although more tests will be necessary, some of our analyses confirm the efforts to improve the representation of the geomagnetic field with more detailed secular variation and acceleration. 2011-05-31T22:00:00Z http://hdl.handle.net/2122/6452 Title: EARTH'S MAGNETISM AT THE SOUTH POLE: A VIEW FROM INLAND AND COASTAL STATIONS AND FROM TEMPORARY INSTALLATIONS Authors: Di Mauro, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cafarella, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Chambodut, A.; Ecole et Observatoire des Sciences de la Terre – Strasburg, France; Lepidi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: Contributions to the knowledge of the Earth’s magnetism from polar regions is extremely important to understand the planetary phenomena which occur both below and above the Earth’s surface. At those areas the Earth’s magnetic field is stronger and the spatial and temporal changes are enhanced. At the same time polar regions are areas scarcely covered by observations for the adverse environmental conditions. We report the experience gained in years of management and maintenance of permanent stations (Mario Zucchelli, Dumont d’Urville (Victoria Land) and Concordia stations, Dome C) as well as temporary installations (Talos Dome) in Antarctica, showing how different acquisition systems, analysis and interpretation of data allow the scientific communities to contribute to originating important theories, models and results. 2010-06-07T22:00:00Z http://hdl.handle.net/2122/6233 Title: On claimed ULF seismogenic fractal signatures in the geomagnetic field Authors: Masci, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: During the last ten years, fractal analysis of ultra-low-frequency (ULF) geomagnetic field components has been proposed as one of the most promising tools to highlight magnetic precursor signals possibly generated by the preparation processes of earthquakes. Several papers claim seismogenic changes in the fractal features of the geomagnetic field some months before earthquakes occur. The target of the present paper is to put forth a qualitative investigation on the fractal characteristics of ULF magnetic signatures that previous authors have claimed to be related without doubt to strong earthquakes. This analysis takes into account both the temporal evolution of the geomagnetic field fractal parameters reported in previous researches and the temporal evolution of global geomagnetic activity. Running averages of the geomagnetic indices ΣKp and Ap are plotted into the original figures from the previous publications. This simple analysis shows that the fractal features of the ULF geomagnetic field are closely related to the geomagnetic activity both before and after the earthquake occurs. The correlation between the geomagnetic field fractal parameters and geomagnetic activity is clearly shown over both long and short time scales. In light of this, the present paper shows that fractal behaviors of previously claimed seismogenic ULF magnetic signatures depend mainly on geomagnetic activity due to solar-terrestrial interaction. Therefore, previously reported association with the preparation process of the earthquake is dubious. 2010-10-18T22:00:00Z http://hdl.handle.net/2122/6197 Title: Human peopling of Italian intramontane basins: The early Middle Pleistocene site of Pagliare di Sassa (L’Aquila, central Italy) Authors: Palombo, M. R.; Dipartimento di Scienze della Terra, Universita` di Roma ‘‘La Sapienza’’, Roma, Italy; Mussi, M.; Dipartimento di Scienze dell’Antichita`, Universita` di Roma ‘‘La Sapienza’’, Roma, Italy; Agostini, S.; Soprintendenza per i Beni Archeologici dell’Abruzzo, Chieti, Italy; Barbieri, M.; CNR, Istituto di Geologia Ambientale e Geoingegneria, Roma, Italy; Di Canzio, E.; Dipartimento di Scienze della Terra, Universita` di Roma ‘‘La Sapienza’’, Roma, Italy; Di Rita, F.; Dipartimento di Biologia Vegetale, Universita` di Roma ‘‘La Sapienza’’, Roma, Italy; Fiore, I.; Via San Rocco, Fiuggi (FR), Italy; Iacumin, P.; Dipartimento di Scienze della Terra, Universita` degli Studi di Parma, Parma, Italy; Magri, D.; Dipartimento di Biologia Vegetale, Universita` di Roma ‘‘La Sapienza’’, Roma, Italy; Speranza, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Tagliacozzo, A.; Museo Nazionale Preistorico-Etnografico ‘‘Luigi Pigorini’’, Roma, Italy Abstract: Multidisciplinary investigations at Pagliare di Sassa (L’Aquila, central Italy) suggest that the local succession accumulated from the late Early to the early Middle Pleistocene in a lacustrine environment. In the upper part, clastic sediments are part of an alluvial fan prograding into the lake, grading to a braided fluvial system. The pollen record confirms that a significant glacial phase occurred just before the onset of the Jaramillo inversion. These data, coupled with evidence from the nearby but earlier Madonna della Strada sequence, allow reconstruction of part of the environmental evolution of L’Aquila basin before the Jaramillo Subchron. The mammal species of Pagliare di Sassa include Stephanorhinus hundsheimensis, mostly of open environments, already present at Madonna della Strada. The faunal turnover characterizing the Early to Middle Pleistocene transition is indicated by the appearances of taxa typical of the Italian early to middle Galerian faunas, such as Praemegaceros verticornis, together with Megaloceros savini. The occurrence of Mimomys savini together with Microtus ex gr. Microtus hintonigregaloides suggests that this assemblage is earlier than the Isernia La Pineta fauna. A flint implement and a fragmentary herbivore femur with impact scars probably linked to human activity give evidence of the human peopling of intramontane basins of the Apennine chain since the early Middle Pleistocene. 2009-12-31T23:00:00Z