Development and Extension of An Aggregated Scale Model: Part 1 – Background to ASMITA     

Ian TOWNEND  Zheng Bing WANG  Marcel STIVE  Zeng ZHOU 《海洋工程》2016,(4):483-504

Whilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorphological elements such as a tidal flat and tidal channel). Such aggregated or lumped models tend not to represent the processes in detail but rather capture the behaviour at the scale of interest. One such model developed using the concept of an equilibrium concentration is the Aggregated Scale Morphological Interaction between Tidal basin and Adjacent coast (ASMITA). In this paper we provide some new insights into the concepts of equilibrium, and horizontal and vertical exchange that are key components of this modelling approach. In a companion paper, we summarise a range of developments that have been undertaken to extend the original model concept, to illustrate the flexibility and power of the conceptual framework. However, adding detail progressively moves the model in the direction of the more detailed process-based models and we give some consideration to the boundary between the two.  相似文献   

An ecosystem-based composite spatial model for floodplain vulnerability assessment: a case study of Artigas,Uruguay     

Freitas  Gabriel  Díaz  Ismael  Bessonart  Martín  da Costa  Edwin  Achkar  Marcel 《GeoJournal》2021,86(3):1155-1171

Floods are natural processes that constitute a hazard to society when associated to improper land use. Anthropic activities in floodplains are a factor of vulnerability that converts a natural hazard into a threat factor, eventually leading to disaster. Nowadays, natural and social complex processes demand integrated assessments in order to improve their understanding, helping decision making over sustainable use of territory, as well as integrating society’s activity in ecosystems and potentials, restrictions and benefits that society obtain from them. In this context, the objective of this work was to build a composite vulnerability model for a floodplain under urban influence, using an integrated assessment approach. This model was based on three dimensions; threat, fragility and an ecosystem services provision. These dimensions were calculated using both primary and secondary information, and weights by specialists. Main results show that the area presents high vulnerability with an increasing gradient towards high and urbanized areas, associated with an important number and relevant ecosystem services. Also, a spatial heterogeneity of the three dimensions emerged, making evident this area’s complexity and the need of integrated assessments to approach it. The composite vulnerability model proposed presents an elevated potential for natural and social processes analysis in floodplains, which is crucial for these territory management. Moreover, these integrated dimensions could contribute to decision making in different levels, as well as generating important supplies for environmental management and land planning.

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Radon in soil anomaly observed at Los Azufres geothermal field,Michoacan: a possible precursor of the 1985 Mexico earthquake (Ms = 8.1)     

N. Segovia  S. de la Cruz-Reyna  M. Mena  E. Ramos  M. Monnin  J. L. Seidel 《Natural Hazards》1989,1(4):319-329

A radon anomaly in a nuclear track detector placed on a fault was detected prior to the destructive (Ms = 8.1) Mexican earthquake of 19 September 1985. The fault is a structural feature of the geothermal field Los Azufres, 260 km NE of the epicentral area. Since no other phenomenon can be found as a possible cause for the radon anomaly, it is proposed that preseismic regional stress perturbations may produce changes in the fluid transport patterns at the fault, suggesting that radon measurements in similar conditions could provide a good precursor in high seismic risk areas.  相似文献   

Proterozoic metavolcanics from western Sierras Pampeanas terrane, Argentina     

G. Vujovich  H. Miller  V.A. Ramos 《Journal of South American Earth Sciences》1994,7(3-4)

A series of medium grade metamorphic rocks of the western sector of the Sierras Pampeanas Terrane in central western Argentina are represented by amphibolites, gneisses and schists derived from sedimentary as well as from igneous rocks. The metavolcanics consist of amphibolites, quartz-K-feldspar-muscovite schists, and hornblende-biotite and biotite-epidote-plagioclase schists. Based on petrographic and geochemical data they are interpreted as originating as basaltic tholeiites, rhyolites and mesosilicic volcanics. The distribution and geochemical behavior are similar to present day western Pacific lavas, mainly those developed on island arcs or heavily attenuated continental crust. Based on these characteristics, an accretionary tectonic model involving a series of island-arc collisions is proposed for the Proterozoic. The complex Proterozoic tectonic history of the western Sierras Pampeanas has been partially obliterated by the emplacement of the Early Paleozoic magmatic arc rocks.  相似文献   

Aspects of the cycle of inorganic nitrogen compounds in the tropical rain forest of the Ivory Coast     

Jean Servant  Robert Delmas  Jacques Rancher  Marcel Rodriguez 《Journal of Atmospheric Chemistry》1984,1(4):391-401

A partial balance of mineral N is given for the basins of two coastal rivers in a forest zone in the Ivory Coast. The dry and wet depositions on the basin surfaces is given for particulate matter (NO₃ ^–, NH₄ ⁺). The quantity of mineral N washed away in the rivers is evaluated. The losses from leaching of the soils by rainwater are about 0.33 to 1.0% of the atmospheric depositions for NH₄ ⁺–N and 2.2 to 5.8% for NO₃ ^––N. The yearly atmospheric input of N compounds to the ecosystem, about 1.4 g N m^–2 y^–1, is at least 14% of mineral N formed in the soils and is therefore quite significant.  相似文献   

The evaporitic celestite-barite deposits of Neuquen,Argentina   总被引：2，自引：0，他引：2  

M. K. de Brodtkorb  V. Ramos  M. Barbieri  S. Ametrano 《Mineralium Deposita》1982,17(3):423-436

Celestite-barite occurrences of early Cretaceous age were studied in the Extra-Andean region of Neuquén, West central Argentina. The ores are located in a Subandean Mesozoic belt and show a conspicuous stratabound character related to evaporitic facies. The study of the geologic evolution of the sedimentary sequence allows prediction of the temporal and spatial setting of the evaporitic facies. Stratigraphy is the main geologic control for the celestite-barite ores and their areal distribution depends on the structure of the region. Based on the geometry and texture of the mineralization three types of ores have been recognized: 1) celestite beds syngenetic with the evaporitic facies; 2) epigenetic stratabound ores formed by "in situ" mobilization of celestite with stalactite growth and cavity infilling; 3) epigenetic vein-type ores formed by mobilized barium enriched solutions.Lithofacies and isotopic ⁸⁷Sr/⁸⁶Sr analyses together with the geological evidence confirm an evaporitic origin for the celestite beds.  相似文献   

Etude des Déformations et Inclinaisons du Sous-sol: Développements Instrumentaux et Applications dans la Région Sismique d’Arette,France     

Philippe Lesage  Pierre Antoine Blum  Marcel Vadell  Jean Francois Fels 《Pure and Applied Geophysics》1983,121(5-6):889-902

We present a modified version of a tilt and strain meter conceived to have great sensibility and good stability. These instruments were deployed in a cave at the seismic Pyrenean region of Arette (France). We set in evidence several types of phenomena, of which deformations brought about by water recharge filling up fissures on the massif are of importance. Owing to the redundance in the data, the study of the co-seismic deformations allows one to separate instrumental displacements and local readjustments from regional motions.  相似文献   

Quantitative analysis of soft-bottom molluscs in the Bellingshausen Sea and around Peter I Island   总被引：2，自引：0，他引：2  

Jesús S. Troncoso  Cristian Aldea  Patrick Arnaud  Ana Ramos  & Francisco García 《Polar research》2007,26(2):126-134

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Andean evolution at the Guañacos and Chos Malal fold and thrust belts (36°30′–37°s)     

Andrs Folguera  Víctor A. Ramos  Toms Zapata  Mauro G. Spagnuolo 《Journal of Geodynamics》2007,44(3-5):129-148

The Andes between 36°30′ and 37°S represent a Cretaceous fold and thrust belt strongly reactivated in the late Miocene. Most of the features that absorbed Neogene shortening were already uplifted in the late Cretaceous, as revealed by field mapping and confirmed by previous fission track analysis. This Andean section is formed by two sectors: a western-inner sector generated by the closure of the upper Oligocene-lower Miocene intra-arc Cura Mallín basin between the middle and late Miocene (Guañacos fold and thrust belt), and an eastern-outer sector, where late Triassic-early Jurassic extensional depocenters were exhumed in two discrete phases of contraction, in the latest early Cretaceous and late Miocene to the Present, respectively (Chos Malal fold and thrust belt). Late Miocene deformation has not homogeneously reactivated Cretaceous compressive structures, being minimal south of 37°30′S through the eastern-outer sector (southern continuation of the Chos Malal fold and thrust belt). The reason for such an inhomogeneous deformational evolution seems to be related to the development of a late Miocene shallow subduction regime between 34°30′ and 37°45′S, as it was proposed in previous studies. This shallow subduction zone is evidenced by the eastward expansion of the arc that was accompanied by the eastern displacement of the orogenic front at these latitudes. As a result, the Cretaceous fold and thrust belt were strongly reactivated north of 37°30′S producing the major topographic break along the Southern Central Andes.  相似文献   

Field‐based and spectral indicators for soil erosion mapping in semi‐arid mediterranean environments (Coastal Cordillera of central Chile)     

Renaud Mathieu  Bernard Cervelle  Dominique Rémy  Marcel Pouget 《地球表面变化过程与地形》2007,32(1):13-31

The Coastal Cordillera of central Chile is naturally sensitive to soil erosion due to moderate to steep slopes, intense winter rains when the vegetation cover is scarce, and deeply weathered granitic rocks. In 1965, 60 per cent of its surface was moderately to very severely eroded. Today this process is still largely active, but no data are currently available to evaluate the real extent, distribution and severity of soil degradation on a regional scale. This information is vital to support efficient soil conservation plans. A multi‐scale approach was implemented to produce regional land degradation maps based on remote sensing technologies. Fieldwork has shown that the surface colour or ‘redness’ and the density of coarse fragments are pertinent erosion indicators to describe a typical sequence of soil degradation in the context of mediterranean soil developed on granitic materials and micaschists. Field radiometric experiments concluded that both factors influence the reflectance of natural surfaces and can be modelled using radiometric indices accessible from most satellites operating in the optical domain, i.e. redness index and brightness index. Finally the radiometric indices were successfully applied to SPOT images to produce land degradation maps. Only broad classes of erosion status were discriminated and the detection of the degradation processes was only possible when most of the fertile layer had already been removed. This technology provides decision‐making information required to develop regional soil conservation plans and to prioritize actions between catchment areas, especially in vast inter‐tropical regions where spatialized data are not always readily available. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献