Morpho-structural setting of Stromboli volcano revealed by high-resolution bathymetry and backscatter data of its submarine portions   总被引：1，自引：0，他引：1  

Alessandro Bosman  Francesco L. Chiocci  Claudia Romagnoli 《Bulletin of Volcanology》2009,71(9):1007-1019

The first high-resolution bathymetric and backscatter maps of offshore Stromboli Island are presented, together with an interpretation of its volcanic, structural and sedimentary features. The volcanic edifice is characterized by a sub-conical shape with a quasi-bilateral symmetry with respect to a NE-SW axis. The dimensions of the Strombolicchio volcanic centre, to the NE of Stromboli, have been restored by redrawing its morphology before wave action that eroded it in Late Quaternary time. On the NE submarine flank of Strombolicchio, a N64°E structural trend controls the shape of Strombolicchio Canyon. On the southern side of Stromboli, the submarine flank has a radial structural trend, possibly reflecting a volcanic stress regime. Landslide scars at various scales are ubiquitous on the submarine slopes of Stromboli. Repeated large-scale lateral collapses have affected both the northwestern and southeastern unbuttressed flanks of the volcano, producing large debris avalanche deposits.  相似文献   

Numerical study of tides in Ontario Lacus,a hydrocarbon lake on the surface of the Saturnian moon Titan     

David Vincent  Özgur Karatekin  Valentin Vallaeys  Alexander G. Hayes  Marco Mastrogiuseppe  Claudia Notarnicola  Véronique Dehant  Eric Deleersnijder 《Ocean Dynamics》2016,66(4):461-482

In the context of the emergence of extra-terrestrial oceanography, we adapted an existing oceanographic model, SLIM (www.climate.be/slim), to the conditions of Titan, a moon of Saturn. The tidal response of the largest southern lake at Titan’s surface, namely Ontario Lacus, is simulated. SLIM solves the 2D, depth-averaged shallow water equations on an unstructured mesh using the discontinuous Galerkin finite element method, which allows for high spatial resolution wherever needed. The impact of the wind forcing, the bathymetry, and the bottom friction is also discussed. The predicted maximum tidal range is about 0.56 m in the southern part of the lake, which is more than twice as large as the previous estimates (see Tokano, Ocean Dyn 60:(4) 803–817 10.1007/s10236-010-0285-3 (Tokano 2010)). The patterns and magnitude of the current are also markedly different from those of previous studies: the tidal motion is not aligned with the major axis of the lake and the speed is larger nearshore. Indeed, the main tidal component rotates clockwise in an exact period of one Titan day and the tidal currents can reach 0.046 ms ^?1 close to the shores depending on the geometry and the bathymetry. Except for these specific nearshore regions, the current speed is less than 0.02 ms ^?1. Circular patterns can be observed offshore, their rotational direction and size varying along the day.  相似文献   

Constraining pre-eruptive magma conditions and unrest timescales during the Monte Nuovo eruption (1538 ad; Campi Flegrei,Southern Italy): integrating textural and CSD results from experimental and natural trachy-phonolites     

Fabio Arzilli  Monica Piochi  Angela Mormone  Claudia Agostini  Michael R. Carroll 《Bulletin of Volcanology》2016,78(10):72

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Climate change and modelling of extreme temperatures in Switzerland   总被引：3，自引：3，他引：0  

Boriss Siliverstovs  Rainald Ötsch  Claudia Kemfert  Carlo C. Jaeger  Armin Haas  Hans Kremers 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(2):311-326

This study models maximum temperatures in Switzerland monitored in twelve locations using the generalised extreme value (GEV) distribution. The parameters of the GEV distribution are determined within a Bayesian framework. We find that the parameters of the underlying distribution underwent a substantial change in the beginning of the 1980s. This change is characterised by an increase both in the level and the variability. We assess the likelihood of the heat wave of the summer 2003 using the fitted GEV distribution by accounting for the presence of a structural break. The estimation results do suggest that the heat wave of 2003 is not that statistically improbable if an appropriate methodology is used for dealing with nonstationarity.  相似文献   

Seismic Hazard Evaluation Using Markov Chains: Application to the Japan Area     

F. Alejandro Nava  Claudia Herrera  José Frez  Ewa Glowacka 《Pure and Applied Geophysics》2005,162(6-7):1347-1366

Seismogenic regions within some geographic area are interrelated through tectonics and seismic history, although this relation is usually complex, so that seismicity in a given region cannot be predicted in a straightforward manner from the activity in other region(s). We present a new statistical method for seismic hazard evaluation based on modeling the transition probabilities of seismicity patterns in the regions of a geographic area during a time interval, as a Markov chain. Application of the method to the Japan area renders good results, considering the occurrence of a high probability transition as a successful forecast. For magnitudes M5.5 and time intervals t=0.10 year, the method yields a 78% aftcast (forecast of data already used to evaluate the hazard) success rate for the entire catalog, and an indicative 80% forecast success rate for the last 10 transitions in the catalog. A byproduct of the method, regional occurrence probabilities determined from the transition probabilities, also provides good results; aftcasts of regional activity have a 98% success rate, and those of activity in the highest probability region about 80.5% success rate. All results are superior to those from the null hypotheses (a memory-less Poissonian, fixed-rate, or uniform system) and have vanishingly small probabilities of resulting from purely random guessing.  相似文献   

Regional Rainfall Depth–Duration–Frequency Equations for an Alpine Region     

Marco Borga  Claudia Vezzani  Giancarlo Dalla Fontana 《Natural Hazards》2005,36(1-2):221-235

In this paper the scaling hypotheses are applied to annual maximum series of rainfall depth for different rainfall duration to derive the depth–duration–frequency (DDF) curve. It is shown that, based on the empirically observed scaling properties of rainfall and some general assumptions about the cumulative distribution function for the annual maximum of the rainfall depth, it is possible to derive a simple DDF relationship. This general framework provides a basis for the generation of maps that can be used to infer DDF curves at any point of a particular area. Data from a dense raingauge network in a mountainous region in north-eastern Italy (the Trentino Province) are used to clarify the methodology for the construction and regionalization of the DDF relationship. The geographical variation of short-duration (i.e., less than 60 xmin) rainfall extremes is also evaluated by using the same framework. It is found that depth–duration ratios, defined as the ratios of the t-min to the 60-min rainfall depths of the same return period, may be considered independent of return period and geographical location for any storm duration less than 60 min.  相似文献   

Thermal characteristics of coal fires 2: Results of measurements on simulated coal fires     

Jianzhong Zhang  Claudia Kuenzer  Anke Tetzlaff  Dieter Oertel  Boris Zhukov  Wolfgang Wagner   《Journal of Applied Geophysics》2007,63(3-4):135-147

In this paper we present thermal characteristics of coal fires as measured during simulated fires under an experimental setting in Germany in July 2002. It is thus a continuation of the previously published paper “Thermal surface characteristics of coal fire 1: Results of in-situ measurement”, in which we presented temperature measurements of real subsurface coal fires in China [Zhang, J., Kuenzer, C., accepted for publication. Thermal Surface Characteristics of Coal Fires 1: Results of in-situ measurements. Accepted for publication at Journal of Applied Geophysics.]. The focus is on simulated coal fires, which are less complex in nature than fires under natural conditions. In the present study we simulated all the influences usually occurring under natural conditions in a controllable manner (uniform background material of known thermal properties, known ventilation pathways, homogeneous coal substrate), creating two artificial outdoor coal fires under simplified settings. One surface coal fire and one subsurface coal fire were observed over the course of 2 days. The set up of the fires allowed for measurements not always feasible under “real” in-situ conditions: thus compared to the in-situ investigations presented in paper one we could retrieve numerous temperature measurements inside of the fires. Single temperature measurements, diurnal profiles and airborne thermal surveying present the typical temperature patterns of a small surface-and a subsurface fire under undisturbed conditions (easily accessible terrain, 24 hour measurements period, homogeneous materials). We found that the outside air temperature does not influence the fire's surface temperature (up to 900 °C), while fire centre temperatures of up to 1200 °C strongly correlate with surface temperatures of the fire. The fires could heat their surrounding up to a distance of 4.5 m. However, thermal anomalies on the background surface only persist as long as the fire is burning and disappear very fast if the heat source is removed. Furthermore, heat outside of the fires is transported mainly by convection and not by radiation. In spatial thermal line scanner data the diurnal thermal patterns of the coal fire are clearly represented. Our experiments during that data collection also visualize the thermal anomaly differences between covered (underground) and uncovered (surface) coal fires. The latter could not be observed in-situ in a real coal fire area. Sub-surface coal fires express a much weaker signal than open surface fires and contrast only by few degrees against the background. In airborne thermal imaging scanner data the fires are also well represented. Here we could show that the mid-infrared domain (3.8 μm) is more suitable to pick up very hot anomalies, compared to the common thermal (8.8 μm) domain. Our results help to understand coal fires and their thermal patterns as well as the limitations occurring during their analysis. We believe that the results presented here can practicably help for the planning of coal fire thermal mapping campaigns — including remote sensing methods and the thermal data can be included into numerical coal fire modelling as initial or boundary conditions.  相似文献   

On Northern Hemisphere Wave Patterns Associated with Winter Rainfall Events in China     

Claudia Christine STEPHAN  Yan Ho NG  Nicholas P.KLINGAMAN 《大气科学进展》2018,35(8):1021-1034

During extended winter(November–April),43% of the intraseasonal rainfall variability in China is explained by three spatial patterns of temporally coherent rainfall.These patterns were identified with empirical orthogonal teleconnection(EOT) analysis of observed 1982–2007 pentad rainfall anomalies and connected to midlatitude disturbances.However,examination of individual strong EOT events shows that there is substantial inter-event variability in their dynamical evolution,which implies that precursor patterns found in regressions cannot serve as useful predictors.To understand the physical nature and origins of the extratropical precursors,the EOT technique is applied to six simulations of the Met Office Unified Model at horizontal resolutions of 200–40 km,with and without air–sea coupling.All simulations reproduce the observed precursor patterns in regressions,indicating robust underlying dynamical processes.Further investigation into the dynamics associated with observed patterns shows that Rossby wave dynamics can explain the large inter-event variability.The results suggest that the apparently slowly evolving or quasi-stationary waves in regression analysis are a statistical amalgamation of more rapidly propagating waves with a variety of origins and properties.  相似文献   

Influence of tidal regime,diurnal phase,habitat and season on feeding of an intertidal crab     

Claudia Bas  Juan P. Lancia  Tomás Luppi  Agustina Méndez‐Casariego  Marcelo Kittlein  Eduardo Spivak 《Marine Ecology》2014,35(3):319-331

The relationship between diet and feeding activity of intertidal crabs, and environmental cycles (tidal, daily and seasonal), habitat and level of the intertidal zone (high/low) was studied using Neohelice granulata (Brachyura, Varunidae) as a model. This is a semi‐terrestrial burrowing crab occupying different habitats in the Southwestern Atlantic coasts and estuaries from bare low intertidal mudflats to high intertidal salt marshes, and from fine, organic matter rich sediment to very coarse sediment with low content of organic matter. The study was carried out in two contrasting habitats of three sites with diverse sets of physical and biological conditions. Diet and feeding of adult N. granulata were indirectly studied through the proportion of food items and the presence/absence of food in crab stomachs, respectively. This species has a dual mode of feeding: predominantly herbivorous (live plants or plant litter in salt marshes) or deposit feeder (superficial sediment and detritus in mudflats), but the quantity and quality of ingested food varies among habitats and sites. A trend to omnivory (including algae and conspecifics) was detected in relation to low quality of resources. Feeding activity modulated by a complex interaction of factors varied according to spatial and/or temporal changes in some natural cycles. Males and non‐ovigerous females fed preferably after dark and during submersion periods, but also after emersion periods if mudflat sediment remained wet; salt marsh crab feeding is somewhat independent of light and tidal cycles. Ovigerous females almost never fed. Both diet and feeding activity of this crab seem to be flexible traits adapted to different combinations of physical and biological factors.  相似文献   

Scenarios for vulnerability: opportunities and constraints in the context of climate change and disaster risk     

Joern Birkmann  Susan L. Cutter  Dale S. Rothman  Torsten Welle  Matthias Garschagen  Bas van Ruijven  Brian O’Neill  Benjamin L. Preston  Stefan Kienberger  Omar D. Cardona  Tiodora Siagian  Deny Hidayati  Neysa Setiadi  Claudia R. Binder  Barry Hughes  Roger Pulwarty 《Climatic change》2015,133(1):53-68

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