Earthquakes in Switzerland and surrounding regions during 2005     

Nicolas Deichmann  Manfred Baer  Jochen Braunmiller  Stephan Husen  Donat F?h  Domenico Giardini  Philipp K?stli  Urs Kradolfer  Stefan Wiemer 《Eclogae Geologicae Helvetiae》2006,99(3):443-452

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15,000 Years of mass-movement history in Lake Lucerne: Implications for seismic and tsunami hazards   总被引：2，自引：0，他引：2  

Michael Schnellmann  Flavio S. Anselmetti  Domenico Giardini  Judith A. Mckenzie 《Eclogae Geologicae Helvetiae》2006,99(3):409-428

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Earthquake-induced deformation structures in lake deposits: A Late Pleistocene to Holocene paleoseismic record for Central Switzerland   总被引：1，自引：0，他引：1  

Katrin Monecke  Flavio S. Anselmetti  Arnfried Becker  Michael Schnellmann  Michael Sturm  Domenico Giardini 《Eclogae Geologicae Helvetiae》2006,99(3):343-362

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Stochastic management of pump-and-treat strategies using surrogate functions   总被引：2，自引：0，他引：2  

Domenico A. Baú  Alex S. Mayer 《Advances in water resources》2006,29(12):1901-1917

Typical pump-and-treat (PAT) optimization problems involve design of pumping schemes, while minimizing cost and meeting a set of constraints. Due to scarcity of information about the hydrogeological system, stochastic modeling approaches can be used to assess tradeoffs between optimality and reliability. Using a stochastic approach, the constrained, single-objective problem may be turned into a multiobjective problem by substituting constraint inequalities with an additional objective function (OF) that accounts for the reliability of the PAT process. In this work, two approaches are analyzed: in one case, the additional OF consists of the probability of failure of a given remediation policy; in another, the OF additional is represented by the recourse, namely the penalty cost induced by the violation of constraints. In order to overcome the overwhelming computational cost required by stochastic simulation, surrogate forms of the OFs are introduced. In the test case under investigation, such functions are estimated by a kriging interpolation of the OF over a series of data points obtained from stochastic simulations of flow and transport, and calibrated against stochastic optimization solutions. The analysis of the two approaches for addressing the tradeoff of cost vs. reliability indicates that recourse accounts not only for the frequency of constraint violations, as the probability of failure does, but also for the intensity with which these occur. Ultimately, the recourse method allows considering less restrictive policies, although these may be highly sensitive to the choice of penalty functions.  相似文献   

Geochemistry of the Submarine Gaseous Emissions of Panarea (Aeolian Islands, Southern Italy): Magmatic vs. Hydrothermal Origin and Implications for Volcanic Surveillance     

Giovanni Chiodini  Stefano Caliro  Giorgio Caramanna  Domenico Granieri  Carmine Minopoli  Roberto Moretti  Lavinia Perotta  Guido Ventura 《Pure and Applied Geophysics》2006,163(4):759-780

The marine sector surrounding Panarea Island (Aeolian Islands, South Italy) is affected by widespread submarine emissions of CO₂ -rich gases and thermal water discharges which have been known since the Roman Age. On November 3^rd, 2002 an anomalous degassing event affected the area, probably in response to a submarine explosion. The concentrations of minor reactive gases (CO, CH₄ and H₂) of samples collected in November and December, 2002 show drastic compositional changes when compared to previous samples collected from the same area in the 1980s. In particular the samples collected after the November 3^rd phenomenon display relative increases in H₂ and CO and a strong decrease in the CH₄ contents, while other gas species show no significant change. The interaction of the original gas with seawater explains the variable contents of CO₂, H₂S, N₂, Ar and He which characterize the different samples, but cannot explain the large variations of CO, CH₄ and H₂ which are instead compatible with changes in the redox, temperature and pressure conditions of the system. Two models, both implying an increasing input of magmatic fluids are compatible with the observed variations of minor reactive species. In the first one, the input of magmatic fluids drives the hydrothermal system towards atypical (more oxidizing) redox conditions, slowly pressurizing the system up to a critical state. In the second one, the hydrothermal system is flashed by the rising high-T volcanic fluid, suddenly released by a magmatic body at depth. The two models have different implications for volcanic surveillance and risk assessment: In the first case, the November 3^rd event may represent both the culmination of a relatively slow process which caused the overpressurization of the hydrothermal system and the beginning of a new phase of quiescence. The possible evolution of the second model is unforeseeable because it is mainly related to the thermal, baric and compositional state of the deep magmatic system that is poorly known.  相似文献   

Volcanic tremor at Mt. Etna: State-of-the-art and perspectives     

S. Gresta  S. Imposa  D. Patané  G. Patané 《Pure and Applied Geophysics》1987,125(6):1079-1095

Volcanic tremor on Etna seems to have its origin within the main magma feeding system. On the basis of both spectral analyses at two permanent seismic stations and periodical measurements along the slopes of the volcano, two distinct sources are proposed. The former, characterized by low frequency contents (f<1.5 Hz), is located in a 2 km deep flat magma chamber, whereas the latter source seems to be linked to the upper part of the active vents.Turbulent motions in the magma-gas mixture, induced by escaping gases within the conduits, is one proposed cause of volcanic tremor on Etna (Seidl et al., 1981).From spectral analyses we propose approximate models of the feeding system of the main summit craters.Time variations of tremor energy were also investigated, and no regular patterns have been observed for the studied eruptions.More systematic information seems to be needed for a better knowledge of both the source model and location, and correlation between tremor features and volcanic activity.  相似文献   

Seismic activity preceding the 1983 eruption of Mt. Etna     

G. Patanè  S. Gresta  S. Imposa 《Bulletin of Volcanology》1984,47(4):941-952

The March–August, 1983 eruption of Mt. Etna can be considered as one of the most important in the last years.The analysis of seismic activity during the three months immediately before the eruption showed interesting variations of theb coefficient, in the frequency-magnitude relationship, that have been linked to possible changes of the stress field in the Etnean region.The eruption start was also preceded by a strong seismic crisis with epicenters mostly on the southern, eastern and southwestern flanks of the volcano, and characterized by the shallowness of most of the events (h3 km).The data analysis has led to a hypothesis on the eruption occurrence based on a model of dynamic evolution of the stress field acting on Mt. Etna.  相似文献   

Extensional shear zones as imaged by reflection seismic lines: the Larderello geothermal field (central Italy)     

Andrea Brogi  Antonio Lazzarotto  Domenico Liotta  Giorgio Ranalli 《Tectonophysics》2003,363(1-2):127-139

The Larderello geothermal field is located in the Inner Northern Apennines, in an area which has been subject to extension since the Early Miocene. The latest extensional episode (Pliocene–Present) has resulted in the formation of NW-trending, NE-dipping listric normal faults, whose geometry is controlled down to 3 km by borehole data. In this paper, we integrate a new interpretation of seismic reflection lines with existing seismic, field, and borehole data to analyse the relations among listric normal faults, the top of the brittle–ductile transition, and the migration of geothermal fluids.In accordance with previous interpretations, we consider the strong reflector (K-horizon) marking the top of the reflective mid-lower crust, and located at a depth of 3–5 km in the geothermal area, to represent the top of the brittle–ductile transition. Its reflectivity most probably derives from the presence of overpressured fluids. We identify three main NW-trending, NE-dipping extensional brittle shear zones, showing listric geometry and soling out in the vicinity of the K-horizon. The latter appears to be dislocated in correspondence of the soling out of the shear zones. These shear zones, because of the associated intense fracturing, represent the most natural channels of upward migration of geothermal fluids from the magmatic sources located below the K-horizon.We suggest that these two conclusions—that listric normal faults root at or near the brittle–ductile transition, and that they act as preferential upward migration paths for magmatic fluids—may be of general validity for geothermal fields located in extensional settings.  相似文献   

Factors Controlling Seismic Susceptibility of the Sele Valley Slopes: The Case of the 1980 Irpinia Earthquake Re-Examined   总被引：3，自引：0，他引：3  

Janusz Wasowski  Vincenzo Pierri  Pierpaolo Pierri  Domenico Capolongo 《Surveys in Geophysics》2002,23(6):563-593

Most of the documented slope failures triggered by the 1980 Irpinia earthquake (M_s 6.9) occurred in the upper Sele valley epicentral area (southern Italy). The early investigations revealed some puzzling characteristics of the slope failure distribution, i.e., (i) the higher landslide concentration on the valley slopes located farther away from the earthquake fault; (ii) the predominance of re-activations over first-time movements. The analyses of factors controlling the landslide concentrations indicates that the differences in hydrological setting and in slope were the two main causal factors whereas the seismic shaking, according to the radiation pattern modelling, could have been characterised by a relatively low rate of decrease across the valley. The aspect of the slopes did not play a significant role. The differences in groundwater conditions between the western and eastern valley sides were probably enhanced by the earthquake. In addition to the probable pore-water pressure rise, the seismic shaking caused large increases in the flow of springs draining the western aquifer, and this made the adjacent flysch slopes more prone to landsliding. Data from the available literature suggest that the effects of earthquake-induced groundwater release on seismic landslide distribution is especially important for normal-fault events. The Sele valley case also indicates that the slope of the pre-existing landslides is an important factor controlling their susceptibility to seismic re-activations.  相似文献   

Palaeoseismicity studies on end-Pleistocene and Holocene lake deposits around Basle, Switzerland   总被引：3，自引：0，他引：3  

Arnfried Becker  Colin A. Davenport  Domenico Giardini 《Geophysical Journal International》2002,149(3):659-678

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