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This article focuses on the Montello thrust system in the Eastern Southern Alps as a potential seismogenic source. This system is of particular interest because of its lack of historical seismicity. Nevertheless, the system is undergoing active deformation. We developed a finite‐element model using visco‐elasto‐plastic rheology. The free parameters of the model (essentially, the locking status of the three thrusts included in the study), were constrained by matching the observed horizontal GPS and vertical levelling data. We show that the amount of interseismic fault locking, and thus the seismic potential, is not necessarily associated with the fastest‐slipping faults. More specifically, the locked Bassano thrust has a greater seismic potential than the freely slipping Montello thrust. The findings suggest that faults with subtle evidence of Quaternary activity should be carefully considered when creating seismic hazard maps. 相似文献
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Joshua Fisher Hannah Stutzman Mariana Vedoveto Debora Delgado Ramon Rivero Walter Quertehuari Dariquebe 《社会与自然资源》2020,33(4):538-553
AbstractGiven the linkages between natural resources and social conflicts, evidence increasingly shows that successful natural resource management requires conflict mitigation and prevention. However, there may be a gap in practice between knowing what processes and tools need to be used to manage conservation conflicts and how to actually implement them. We present learning from a practice-based case study of conflict management in the Amarakaeri Communal Reserve in the Peruvian Amazon that aimed to develop natural resource governance institutions and build stakeholder capacity, including of indigenous groups, to navigate existing conflict resolution mechanisms. Through applying good practices in conservation conflict management and collaborative governance, we generated important lessons on the practical considerations involved in collaborative conservation. These lessons, while specific to our case, could be applied to a variety of protected areas facing complex social-ecological systems dynamics and wicked problems. 相似文献
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This paper deals with the interaction and small-scale processes occurring around the inlets that connect the Venice Lagoon
with the Northern Adriatic Sea. In a previous paper, barotropic processes have been investigated, whereas here, the focus
is on the baroclinic processes. The hydrodynamics of the area are studied by means of a 3D shallow water hydrodynamic finite-element
model, suitable to describe areas of complex morphology such as the coasts and the interaction channels. This is the first
work that models the 3D interaction between the Venice Lagoon and the Adriatic Sea. Three different sets of simulations have
been carried out to identify the physics behind the small-scale processes and the influence of the main forcings on the study
area. The first imposes different idealized forcings, such as tides, wind, and river runoff. The vorticity maps of the first
two layers show the predominance of wind forcing in the coastal area and tidal forcing in the three inlets of the Lagoon.
Bora wind acts homogeneously, increasing the littoral currents, while Sirocco wind mainly impacts near Chioggia inlet, with
a coastal current reversal, inducing its detachment offshore. Freshwater patterns are present along the coast, near the river
mouths. Rivers do not directly influence the circulation close to the coast in front of the Venice Lagoon, except for the
area near Chioggia inlet, where the Brenta river action can be seen. The second set of simulations deals with a sensitivity
analysis to define the importance of the advection and of the baroclinic pressure gradient terms in the creation of persistent
structures, such as small-scale coastal vortices seen along the littoral very close to the inlets. This analysis shows how
advection is the main physical process responsible for the persistence of the positive vorticity structures close to the coast
between the inlets, while the negative vorticity structures, also seen by the HF Radar, are due to the baroclinic-advective
interaction. Finally, a real case, year 2004, has been simulated both to validate the model with observations and to identify
the occurrence during the year of the characteristic hydrodynamic features attributable to the main forcings. The action of
Bora wind characterizes the surface current patterns of February and November 2004, while Sirocco influences the month of
May 2004. During periods of weak wind, the model reproduces the small-scale vortical structures close to the littoral. 相似文献
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Andrew Moore James Goff Brian G. McAdoo Hermann M. Fritz Aditya Gusman Nikos Kalligeris Kenia Kalsum Arif Susanto Debora Suteja Costas E. Synolakis 《Pure and Applied Geophysics》2011,168(11):1951-1961
The 2006 western Java tsunami deposited a discontinuous sheet of sand up to 20 cm thick, flooded coastal southern Java to
a depth of at least 8 m and inundated up to 1 km inland. In most places the primarily heavy mineral sand sheet is normally
graded, and in some it contains complex internal stratigraphy. Structures within the sand sheet probably record the passage
of up to two individual waves, a point noted in eyewitness accounts. We studied the 2006 tsunami deposits in detail along
a flow parallel transect about 750 m long, 15 km east of Cilacap. The tsunami deposit first becomes discernable from the underlying
sediment 70 m from the shoreline. From 75 to 300 m inland the deposit has been laid down in rice paddies, and maintains a
thickness of 10–20 cm. Landward of 300 m the deposit thins dramatically, reaching 1 mm by 450 m inland. From 450 m to the
edge of deposition (around 700 m inland) the deposit remains <1 mm thick. Deposition generally attended inundation—along the
transect, the tsunami deposited sand to within about 40 m of the inundation limit. The thicker part of the deposit contains
primarily sand indistinguishable from that found on the beach 3 weeks after the event, but after about 450 m (and roughly
coinciding with the decrease in thickness) the tsunami sediment shifts to become more like the underlying paddy soil than
the beach sand. Grain sizes within the deposit tend to fine upward and landward, although overall upward fining takes place
in two discrete pulses, with an initial section of inverse grading followed by a section of normal grading. The two inversely
graded sections are also density graded, with denser grains at the base, and less dense grains at the top. The two normally
graded sections show no trends in density. The inversely graded sections show high density sediment to the base and become
less dense upward and represents traction carpet flows at the base of the tsunami. These are suggestive of high shear rates
in the flow. Because of the grain sorting in the traction carpet, the landward-fining trends usually seen in tsunami deposits
are masked, although lateral changes of mean sediment grain size along the transect do show overall landward fining, with
more variation as the deposit tapers off. The deposit is also thicker in the more seaward portions than would be produced
by tsunamis lacking traction carpets. 相似文献
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A hydrodynamic model of the Venice Lagoon and the Adriatic Sea has been developed in order to study the exchanges at the inlets of the Venice Lagoon, a complex morphological area connecting the sea and the lagoon. The model solves the shallow water equations on a spatial domain discretized by a staggered finite element grid. The grid represents the Adriatic Sea and the Venice Lagoon with different spatial resolutions varying from 30 m for the smallest channels of the lagoon to 30 km for the inner areas of the central Adriatic Sea. Data from more than ten tide gauges displaced in the Adriatic Sea have been used in the calibration of the simulated water levels. After the calibration, the tidal wave propagation in the North Adriatic and in the Venice Lagoon is well reproduced by the model. To validate the model results, empirical flux data measured by acoustic Doppler current profiler probes installed inside the inlets of Lido and Malamocco have been used and the exchanges through the three inlets of the Venice Lagoon have been analyzed. The comparison between modeled and measured fluxes at the inlets outlines the efficiency of the model to reproduce both tide- and wind-induced water exchanges between the sea and the lagoon. Even in complex areas, where highly varying resolution is needed, the model is suitable for the simulation of the dominating physical processes. 相似文献
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Taniel Danelian Laurence Le Callonnec Jochen Erbacher David C. Mosher Mitchell J. Malone Debora Berti Karen L. Bice Helen Bostock Hans-Jürgen Brumsack Astrid Forster Felix Heidersdorf Jorijntje Henderiks Thomas J. Janecek Christopher Junium Ken MacLeod Philip A. Meyers Jörg H. Mutterlose Hiroshi Nishi Christine Glatz 《Comptes Rendus Geoscience》2005,337(6):609-616
Five sites located on a bathymetric transect of the distal Demerara Rise were studied by ODP Leg 207. Albian sediments of essentially terrigenous nature (clay, siltstone, sandstone) are the oldest drilled stratigraphic levels and form apparently the top of the synrift sequence. They are overlain by Cenomanian to Santonian finely laminated black shales, rich in organic matter of marine origin, which accumulated on a thermally subsiding ramp. Early Campanian hiatuses are thought to be the result of final disjunction of Demerara Rise (South America) from Africa and the onset of deep water communication between the two Atlantic basins (south and central). The overlying Uppermost Cretaceous–Oligocene chalk includes rich and diversified calcareous plankton assemblages, as well as two radiolarian-rich intervals (Late Campanian and Middle Eocene). A complex erosional surface developed during the Late Oligocene–Early Miocene. Sedimentation was impeded since then on the intermediate and deep sites of Demerara Rise, possibly due to the action of deep submarine currents. To cite this article: T. Danelian et al., C. R. Geoscience 337 (2005). 相似文献
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A fast and global two point low storage optimization technique for tracing rays in 2D and 3D isotropic media 总被引：1，自引：0，他引：1
We present the problem of tracing rays in 2D and 3D heterogeneous isotropic media as a set of optimization problems. Each optimization problem is obtained by applying Fermat's principle to an approximation of the travel time equation from a fixed source to a fixed receiver. We assume a piecewise linear ray path that simplifies the computations of the problem, in the same way Mao and Stuart suggested in a very recent paper. Here, instead, the reflector geometry and the velocity function are computed by using nonuniformly biharmonic splines. On the other hand, to solve the optimization problem we use the Global Spectral Gradient method. This recent developed optimization scheme is a low storage optimization technique that requires very few floating point operations. It only requires the gradient of the travel time function, and it is global because it converges independently of the initial guess, that is, it does not require a close initial ray path. These three properties of the optimization method and the assumption of piecewise linear rays make this ray tracing scheme a very fast, global and effective method when estimating velocities via tomography. Moreover, in a homogeneous stratified or dipped media, any solution of the optimization problem is the best solution, i.e., it is the global minimum, no matter what numerical approach is used. We present some numerical results that show the computational advantages and the performance of this ray tracing in homogeneous and heterogeneous media. 相似文献
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This study shows how the use of increasing model complexity allows us to hypothesize about dominant streamflow mechanisms in two small Brazilian forested basins. Nine different structures from SUPERFLEX, an objective framework to systematically increase hydrological model complexity, were tested and we extended the flexible modelling methodology to error models as well. We show that applying a rigorous methodology in a model evaluation framework, with residual analysis and control of model complexity, is essential for testing a model as a hypothesis for dominant hydrological controls. Our results indicate that the model architecture was more important than the increase in the number of model parameters. Better performing models were those with a parallel structure, which confirms our a priori belief about the dominant runoff mechanisms of the studied catchments, characterized by a rapid response to rainfall, but also a constant river discharge fed by water storage on the thick soil layer. 相似文献