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51.
Tephra layers from archaeological sites in southern Italy and eastern Europe stratigraphically associated with cultural levels containing Early Upper Palaeolithic industry were analysed. The results confirm the occurrence of the Campanian Ignimbrite tephra (CI; ca. 40 cal ka BP) at Castelcivita Cave (southern Italy), Temnata Cave (Bulgaria) and in the Kostenki–Borshchevo area of the Russian Plain. This tephra, originated from the largest eruption of the Phlegrean Field caldera, represents the widest volcanic deposit and one of the most important temporal/stratigraphic markers of western Eurasia. At Paglicci Cave and lesser sites in the Apulia region we recognise a chemically and texturally different tephra, which lithologically, chronologically and chemically matches the physical and chemical characteristics of the Plinian eruption of Codola; a poorly known Late Pleistocene explosive event from the Neapolitan volcanoes, likely Somma–Vesuvius. For this latter, we propose a preliminary age estimate of ca. 33 cal ka BP and a correlation to the widespread C-10 marine tephra of the central Mediterranean. The stratigraphic position of both CI and Codola tephra layers at Castelcivita and Paglicci help date the first and the last documented appearance of Early Upper Palaeolithic industries of southern Italy to ca. 41–40 and 33 cal ka BP, respectively, or between two interstadial oscillations of the Monticchio pollen record – to which the CI and Codola tephras are physically correlated – corresponding to the Greenland interstadials 10–9 and 5. In eastern Europe, the stratigraphic and chronometric data seem to indicate an earlier appearance of the Early Upper Palaeolithic industries, which would predate of two millennia at least the overlying CI tephra. The tephrostratigraphic correlation indicates that in both regions the innovations connected with the so-called Early Upper Palaeolithic – encompassing subsistence strategy and stone tool technology – appeared and evolved during one of the most unstable climatic phases of the Last Glacial period. On this basis, the marked environmental unpredictability characterising this time-span is seen as a potential ecological factor involved in the cultural changes observed.  相似文献   
52.
Systematic in situ analysis of active fault zones in Val d’Agri (southern Italy) suggests that the acquisition of quantitative data on fault-related structural discontinuities is fundamental for (1) discriminating between the latter and older regional features, (2) defining the architecture and related permeability structure of faults, and (3) performing simple statistics in order to evaluate the validity range within which fault characteristics may be considered to be fractals. This type of information can be integrated with regional seismotectonic analysis in order to asses the present-day conditions of deformation characterising the area, and to constrain the possible kinematics of the seismogenic structures controlling earthquake activity in this sector of the southern Apennines. The results of our study are also of interest for modelling earthquake sources, since a knowledge of the permeability structure and scaling properties of a faulted rock volume is potentially relevant for simulating the time and space dependent behaviour of fault zones during a seismic cycle.  相似文献   
53.
A detailed numerical simulation of the ground motion and a site response analysis for two towns in the Marche Region (Treia and Cagli) is carried out on the basis of structural models deduced from available geological and geophysical data. In both cases, the reference event is an M = 5.7 earthquake associated with a normal fault located beneath each town. The ground motion is computed using the 2D spectral element method (SPEM 2D). The method solves the propagation of the seismic field through complex geological structures and enables an estimate of the effects of deep crustal structure, superficial geology, and topography on ground motion. Numerical simulations of the seismic field are performed along 2D vertical planes containing the seismic source. Strong ground motion has not been yet recorded in the two towns; therefore, the numerical simulation of ground motion represents a way to overcome the lack of instrumental data. The simulations carried out for Treia show that ground motion is influenced by both source mechanism and effects due to propagation through the geological structure, while ground motion in Cagli features strong local effects, caused by the presence of alluvial deposits under a large area of the town.  相似文献   
54.
Ocean Dynamics - The tides in the Mediterranean Sea are generally weaker than in other regions of the world ocean, but are locally intensified in passages with complex bathymetry, such as the...  相似文献   
55.
Urban Computing is a branch of Pervasive Computing that investigates urban settings and everyday lifestyles. A large quantity of information to develop pervasive applications for urban environments is often already available, even if scattered and not integrated: maps, points of interest, user locations, traffic, pollution, and events are just a few examples of the digitalized information which we can access on the Web. Applications for mobile users that leverage such information are rapidly growing. In this article, we report our experience in addressing practical computational issues influencing the use of Geographic Information Systems and geospatial data from the standpoint of semantics and pervasive computing. We refer to the early achievements of the LarKC project, in which we developed an Urban Computing demonstrator. We highlight the positive sides of our experience and we discuss open issues and possible advances.  相似文献   
56.
At ~20 ka bp , lakes Yehuin, Chepelmut and Fagnano constituted a single, large water body in the central part of Isla Grande de Tierra del Fuego (southernmost Patagonia). The evolutionary history of this lake, known as ‘Palaeolago Fueguino’, was probably controlled by the advances, stillstands and retreats of the ‘Fagnano Palaeoglacier’, an outlet glacier that flowed eastward from the Darwin Cordillera ice sheet. A detailed analysis of high-resolution seismic reflection profiles acquired within the three lakes has allowed the identification and correlation of seven unconformities within the lacustrine sedimentary infill, three seismostratigraphic sequences in Lago Fagnano and four in Lago Yehuin. A seismic stratigraphic correlation between these sequences suggests that these basins formerly constituted a single, large lacustrine body. A lake-level curve of the evolutionary stages of each lake, derived from the seismostratigraphic analysis of the sedimentary infill is proposed here, representing a 17.5 ka-long record. It was further integrated with the glacial record of the advances and retreats of the Fagnano Palaeoglacier. This study has implications for interpreting the sedimentary history of lake basins in glaciated mountain ranges.  相似文献   
57.
58.
The development and widespread use of statistical learning models have brought the need for tools that help analysts diagnose, build, and refine those models. In this work, in particular, we focus on interpolation models, which spatially predict the value of a variable based on the values of its neighborhood. Investigating these results spatially or comparing them with other models at different levels of granularity is still a challenge for the analysts trying to understand and refine their models. To deal with that, we propose a visual analytics model-agnostic tool for facilitating the comparison and refinement of spatial models at different levels of granularity using interactive visualization techniques. The tool was built in collaboration with specialists who used it to diagnose and improve a spatial model for predicting residential real estate prices.  相似文献   
59.
Integrated classification maps were produced by combining sediment grain-size and hydrological data (water renewal time, WRT) from two Mediterranean lagoons, Lesina (LL) and Varano (LV), Italy. The geophysical characteristics of the two basins, derived from detailed bathymetric charts, are quite distinct: ~30% of LL (mean depth ~1 m) but only 3% of LV (mean depth ~3 m) is shallower than 1 m. The sediments of both lagoons are mainly composed of mud (~80%). A detailed multivariate analysis of grain-size data by EntropyMax classified the lagoon beds of LL and LV into five sedimentary facies. WRT data, computed by a hydrodynamic model, indicated different hydrological conditions in the two lagoons: LL showed a sharp west–east gradient, with a basin-wide average of ~190 days, whilst LV showed a fairly uniform distribution and a higher basin-wide average (~260 days). The distribution of sedimentary facies and water renewal times were combined in a composite map representing the distribution of environmental patterns. The approach outlined in this study can be used to improve zonation schemes by providing a hydromorphological perspective on transitional and coastal environments.  相似文献   
60.
In Mediterranean coastal catchments, water management for preservation of pine forests and other natural areas faces particular challenges. Limited rainfall, water consumption by vegetation as well as subsidence, drainage and salt water intrusion all play an important role. Traditionally forest and water management are carried out independent of one another and do not consider water budget calculations. We show with this study that is very important to have quantitative information of all the components of the water budget as well as the size of the fresh water lenses in the aquifer to be able to integrate the water- and forest management. We use an integrated hydrologic-ecologic methodology based on easily attainable data to assess the monthly water budget of a coastal catchment, Marina Romea (Ravenna, Italy). We present detailed monthly water table records, rainfall data, drainage data, tree density and tree perimeter and use published sap flow measurements of single pine trees (Pinus Pinea) to quantify the actual transpiration of single pine trees in different periods of the year. Transpiration amounts to 10–30 l per day per tree. These values are confirmed by independent estimates of tree transpiration based on our water budget calculations: 9–34 l/tree/day. Because typically there are so many trees in planted pine forests, the total transpiration rates over the whole watershed take up a large percentage (up to 200 %) of the precipitation. In Marina Romea, four monitoring periods out of twelve, the tree transpiration is larger than precipitation. In nine monitoring periods, drainage in the watershed is larger than precipitation or tree water transpiration. The measurements and calculations show that not much freshwater is left to recharge the fresh water lens underneath Marina Romea. Monthly monitoring of groundwater table elevation and salinity in the pine forest of Marina Romea from March 2007 to February 2008 shows that the groundwater table strongly fluctuates and groundwater salinity is constantly very high (up to 17.7 g/l). Analytical calculations based on the Ghyben Herzberg Dupuit principle suggest that even a small continuous annual recharge of 15 mm could form a 2-m deep freshwater lens in the unconfined aquifer. This freshwater lens is not present in the study area and this is due to the fact that tree water transpiration and drainage take out most of the fresh water coming into the watershed. In catchments like Marina Romea, water consumption by the (natural) vegetation and seasonal differences as well as the fact that fresh water lenses are limited in salty surroundings should be taken into account in water and forest management.  相似文献   
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