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31.
32.
Manfred F. Buchroithner Guido Ehlert Bernd Hetze Horst Kohlschmidt Nikolas Prechtel 《Pure and Applied Geophysics》2014,171(6):1077-1087
Mountain-rescue operations require rapid response whilst also ensuring the security of the rescue teams. Rescuing people in a big rock-face is even more difficult if night or fog prevent sight. The paper presents a technical solution to optimally support, under these aggravated conditions, the location of the casualties and the navigation of the rescue team(s) in a rock-face from a coordination station. In doing so, standard components like a smartphones with GPS functionality, a data communication on a client–server basis and VR visualisation software have been adapted to the specific requirements. Remote support of the navigation in steep rocky terrain requires a highly accurate wall model which permits the local experts of the coordination station to dependably estimate geometry and structure of the rock along the rescue route and to convey necessary directives to the retrieval team. Based on terrestrial laser-scans from different locations, such a model has been generated for the mighty Dachstein South Face (Austria) and texturised with digital photographs. Over a twelve-month period, a transdisciplinary team of the Dresden University of Technology (Informatics, Electrical Engineering, Cartography) developed and integrated the various technical modules of the mountain-rescue support-system (digital rock-face model, optimised GPS data transmission between mobile device, server and client, data filtering, and dynamic visualisation component). In summer 2011 the proper functioning of the prototype was demonstrated in a rescue exercise under foggy dusk conditions. 相似文献
33.
A framework for the seismic assessment of existing masonry buildings accounting for different sources of uncertainty
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The current formulation of Eurocode 8 Part 3 and the Italian building code for the seismic assessment of existing buildings accounts for epistemic (knowledge‐based) uncertainties by means of the identification of knowledge levels with associated values of the so‐called confidence factors, applied only as a reduction of material strengths. This formulation does not always produce consistent results and it does not explicitly account for other sources of uncertainty. The paper proposes a probabilistic methodology for the quantification of appropriately defined factors, allowing consideration of the different sources of uncertainty involved in the seismic assessment of masonry buildings by means of nonlinear static analyses. This simple approach, also including an alternative formulation of the confidence factors related with material properties, allows to obtain results which are consistent with the acquired level of knowledge and correctly account for the different sources of uncertainty without requiring to carry out any stochastic nonlinear analysis. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
34.
Daniel Rufer Frank Preusser Guido Schreurs Edwin Gnos Alfons Berger 《Bulletin of Volcanology》2014,76(5):1-20
The Quaternary Vakinankaratra volcanic field in the central Madagascar highlands consists of scoria cones, lava flows, tuff rings, and maars. These volcanic landforms are the result of processes triggered by intracontinental rifting and overlie Precambrian basement or Neogene volcanic rocks. Infrared-stimulated luminescence (IRSL) dating was applied to 13 samples taken from phreatomagmatic eruption deposits in the Antsirabe–Betafo region with the aim of constraining the chronology of the volcanic activity. Establishing such a chronology is important for evaluating volcanic hazards in this densely populated area. Stratigraphic correlations of eruption deposits and IRSL ages suggest at least five phreatomagmatic eruption events in Late Pleistocene times. In the Lake Andraikiba region, two such eruption layers can be clearly distinguished. The older one yields ages between 109?±?15 and 90?±?11 ka and is possibly related to an eruption at the Amboniloha volcanic complex to the north. The younger one gives ages between 58?±?4 and 47?±?7 ka and is clearly related to the phreatomagmatic eruption that formed Lake Andraikiba. IRSL ages of a similar eruption deposit directly overlying basement laterite in the vicinity of the Fizinana and Ampasamihaiky volcanic complexes yield coherent ages of 68?±?7 and 65?±?8 ka. These ages provide the upper age limit for the subsequently developed Iavoko, Antsifotra, and Fizinana scoria cones and their associated lava flows. Two phreatomagmatic deposits, identified near Lake Tritrivakely, yield the youngest IRSL ages in the region, with respective ages of 32?±?3 and 19?±?2 ka. The reported K-feldspar IRSL ages are the first recorded numerical ages of phreatomagmatic eruption deposits in Madagascar, and our results confirm the huge potential of this dating approach for reconstructing the volcanic activity of Late Pleistocene to Holocene volcanic provinces. 相似文献
35.
Andrea Penna Paolo Morandi Maria Rota Carlo Filippo Manzini Francesca da Porto Guido Magenes 《Bulletin of Earthquake Engineering》2014,12(5):2255-2273
The earthquake sequence started on May \(20\) th 2012 in Emilia (Italy) affected a region where masonry constructions represent a large part of the existing building stock and the construction of new modern masonry buildings is a common practice. The paper is focused on the performance of common architectural configurations, typical for residential or business use. The large majority of old masonry buildings is made of fired clay bricks. The seismic performance of these buildings is particularly interesting since major past earthquakes in Italy affected areas with mainly stone masonry structures. Apart from examples showing systematic or peculiar structural deficiencies governing the vulnerability of several buildings, the overall seismic performance of these structures to repeated shaking, with PGA as large as 0.25–0.3 g was rather good, despite the major part of them were only conceived for carrying vertical loads. In fact, seismic design is mandatory in the area only since 2003. Modern low-rise masonry buildings erected after this date and incorporating seismic design and proper detailing resulted in most cases practically undamaged. The examples reported in the paper allow an evaluation of the superior performance of seismically designed modern masonry buildings in comparison to older ones. 相似文献
36.
Multidisciplinary inferences on a newly recognized active east‐dipping extensional system in Central Italy
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Giusy Lavecchia Guido Maria Adinolfi Rita de Nardis Federica Ferrarini Daniele Cirillo Francesco Brozzetti Raffaella De Matteis Gaetano Festa Aldo Zollo 《地学学报》2017,29(1):77-89
We use a multidisciplinary approach to gather preliminary evidence for a Quaternary east‐dipping extensional detachment in Central Italy. This structure crops out in the Sabini‐Eastern Simbruini (SES) and would be hidden at mid‐crustal depths beneath the L'Aquila 2009 (Mw6.3) epicentral area. The SES geometry is reconstructed through geological mapping, structural analysis and seismic line interpretation. The geometry of the mid‐crustal segment, referred to as the Ocre Segment (OS), is interpreted through seismological analyses of the largest aftershock (Mw5.4) of the L'Aquila 2009 sequence. The kinematic compatibility between the SES and the OS under a common SW–NE tensional field is tested through stress inversion of both geological and seismological data. The reliability of OS activation is tested through slip tendency analysis. Like other Italian cases, the SES and the OS are preliminarily interpreted as expressions at different depths of the same unknown east‐dipping extensional detachment, characterized by a ramp–flat–ramp geometry. 相似文献
37.
Satellite services that deliver information about possible oil spills at sea currently use different labels of “confidence” to describe the detections based on radar image processing. A common approach is to use a classification differentiating between low, medium and high levels of confidence. There is an ongoing discussion on the suitability of the existing classification systems of possible oil spills detected by radar satellite images with regard to the relevant significance and correspondence to user requirements. This paper contains a basic analysis of user requirements, current technical possibilities of satellite services as well as proposals for a redesign of the classification system as an evolution towards a more structured alert system. This research work offers a first review of implemented methodologies for the categorisation of detected oil spills, together with the proposal of explorative ideas evaluated by the European Group of Experts on satellite Monitoring of sea-based oil Pollution (EGEMP). 相似文献
38.
Modeling ground deformations of Panarea volcano hydrothermal/geothermal system (Aeolian Islands, Italy) from GPS data 总被引:1,自引:0,他引:1
Alessandra Esposito Marco Anzidei Simone Atzori Roberto Devoti Guido Giordano Grazia Pietrantonio 《Bulletin of Volcanology》2010,72(5):609-621
Panarea volcano (Aeolian Islands, Italy) was considered extinct until November 3, 2002, when a submarine gas eruption began
in the area of the islets of Lisca Bianca, Bottaro, Lisca Nera, Dattilo, and Panarelli, about 2.5 km east of Panarea Island.
The gas eruption decreased to a state of low degassing by July 2003. Before 2002, the activity of Panarea volcano was characterized
by mild degassing of hydrothermal fluid. The compositions of the 2002 gases and their isotopic signatures suggested that the
emissions originated from a hydrothermal/geothermal reservoir fed by magmatic fluids. We investigate crustal deformation of
Panarea volcano using the global positioning system (GPS) velocity field obtained by the combination of continuous and episodic
site observations of the Panarea GPS network in the time span 1995–2007. We present a combined model of Okada sources, which
explains the GPS results acquired in the area from December 2002. The kinematics of Panarea volcano show two distinct active
crustal domains characterized by different styles of horizontal deformation, supported also by volcanological and structural
evidence. Subsidence on order of several millimeters/year is affecting the entire Panarea volcano, and a shortening of 10−6 year−1 has been estimated in the Islets area. Our model reveals that the degassing intensity and distribution are strongly influenced
by geophysical-geochemical changes within the hydrothermal/geothermal system. These variations may be triggered by changes
in the regional stress field as suggested by the geophysical and volcanological events which occurred in 2002 in the Southern
Tyrrhenian area. 相似文献
39.
Jacopo Taddeucci Gianluca Sottili Danilo M. Palladino Guido Ventura Piergiorgio Scarlato 《Bulletin of Volcanology》2010,72(1):75-83
Hydromagmatic eruptions convert thermal into mechanical energy via the expansion of ground- and/or surface-water. Several
models address the energetics of these eruptions based on different physical-volcanological approaches. Here we test different
models with two case studies in the Colli Albani Volcanic District (central Italy): the monogenetic Prata Porci and the polygenetic
Albano maars. Test results are mutually consistent, and show cumulative mechanical energy releases on the order of 1015–1017 J for single maars. The fraction of thermal energy turned into mechanical ranges from 0.45 (as calculated from the theoretical
maximum mechanical energy), through 0.1 (calculated from country rock fragmentation, crater formation and ballistic ejection),
to 0.03 (derived from magma fragmentation by thermohydraulic explosions). It appears that the energy released during the most
intense hydromagmatic events may account for a dominant fraction of the total mechanical energy released during the whole
maar eruptive histories. Finally, we consider the role of magmatic explosive activity intervening during maar eruptions in
causing departures from predictions of the models evaluated. 相似文献
40.
ABSTRACTThere is a lack of suitable methods for creating precipitation scenarios that can be used to realistically estimate peak discharges with very low probabilities. On the one hand, existing methods are methodically questionable when it comes to physical system boundaries. On the other hand, the spatio-temporal representativeness of precipitation patterns as system input is limited. In response, this paper proposes a method of deriving spatio-temporal precipitation patterns and presents a step towards making methodically correct estimations of infrequent floods by using a worst-case approach. A Monte Carlo approach allows for the generation of a wide range of different spatio-temporal distributions of an extreme precipitation event that can be tested with a rainfall–runoff model that generates a hydrograph for each of these distributions. Out of these numerous hydrographs and their corresponding peak discharges, the physically plausible spatio-temporal distributions that lead to the highest peak discharges are identified and can eventually be used for further investigations.
Editor A. Castellarin; Associate editor E. Volpi 相似文献