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1.
Bianca Carvalho Vieira Nelson Ferreira Fernandes Oswaldo Augusto Filho Tiago Damas Martins David R. Montgomery 《Environmental Earth Sciences》2018,77(6):260
The hillslopes of the Serra do Mar, a system of escarpments and mountains that extend more than 1500 km along the southern and southeastern Brazilian coast, are regularly affected by heavy rainfall that generates widespread mass movements, causing large numbers of casualties and economic losses. This paper evaluates the efficiency of susceptibility mapping for shallow translational landslides in one basin in the Serra do Mar, using the physically based landslide susceptibility models SHALSTAB and TRIGRS. Two groups of scenarios were simulated using different geotechnical and hydrological soil parameters, and for each group of scenarios (A and B), three subgroups were created using soil thickness values of 1, 2, and 3 m. Simulation results were compared to the locations of 356 landslide scars from the 1985 event. The susceptibility maps for scenarios A1, A2, and A3 were similar between the models regarding the spatial distribution of susceptibility classes. Changes in soil cohesion and specific weight parameters caused changes in the area of predicted instability in the B scenarios. Both models were effective in predicting areas susceptible to shallow landslides through comparison of areas predicted to be unstable and locations of mapped landslides. Such models can be used to reduce costs or to define potentially unstable areas in regions like the Serra do Mar where field data are costly and difficult to obtain. 相似文献
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Miguel Angelo Stipp Basei Benjamim Bley Brito Neves Oswaldo Siga Junior Marly Babinski Marcio Martins Pimentel Colombo Celso Gaeta Tassinari Maria Helena Bezerra Hollanda Allen Nutman Umberto Giuseppe Cordani 《Precambrian Research》2010
The South-American continent is constituted of three major geologic–geotectonic entities: the homonym platform (consolidated at the end of the Cambrian), the Andean chain (essentially Meso-Cenozoic) and the Patagonian terrains, affected by tectonism and magmatism through almost all of the Phanerozoic. The platform is constituted by a series of cratonic nuclei (pre-Tonian, fragments of the Rodinia fission) surrounded by a complex fabric of Neoproterozoic structural provinces. 相似文献
4.
Kristin N. Safi Oswaldo Chinchilla Mazariegos Carl P. Lipo Hector Neff 《Geoarchaeology》2012,27(5):410-425
The Cotzumalhuapa Nuclear Zone (CNZ) is a Late Classic site consisting of three large architectural compounds linked by a series of stone‐paved causeways and bridges. The majority of the site, however, lies beneath layers of recent tephra, leaving the structure of this settlement largely unknown. This study uses ground‐penetrating radar (GPR) to map the subsurface near El Baúl, one of the main compounds, in order to examine the spatial relationship among urban architectural features. Excavation within areas of the GPR survey provides fine‐grain detail of one major architectural feature in the region, the Gavarrete Causeway. The complimentary nature of these data sets characterizes the architectural organization of the settlement at two scales. Spatial patterning between large‐scale architectural features supports the hypothesis that the CNZ represents an integrated urban center with evidence of planned community organization characteristic of other Late Classic period centers across Mesoamerica. 相似文献
5.
This paper presents a method for transforming the information of an engineering geological map into useful information for
non-specialists involved in land-use planning. The method consists of classifying the engineering geological units in terms
of land use capability and identifying the legal and the geologic restrictions that apply in the study area. Both informations
are then superimposed over the land use and a conflict areas map is created. The analysis of these data leads to the identification
of existing and forthcoming land use conflicts and enables the proposal of planning measures on a regional and local scale.
The map for the regional planning was compiled at a 1:50,000 scale and encompasses the whole municipal land area where uses
are mainly rural. The map for the local planning was compiled at a 1:10,000 scale and encompasses the urban area. Most of
the classification and operations on maps used spatial analyst tools available in the Geographical Information System. The
regional studies showed that the greater part of Analandia’s territory presents appropriate land uses. The local-scale studies
indicate that the majority of the densely occupied urban areas are in suitable land. Although the situation is in general
positive, municipal policies should address the identified and expected land use conflicts, so that it can be further improved. 相似文献
6.
Oswaldo Eduardo Ramos Ramos Luis Fernando Cáceres Mauricio Rodolfo Ormachea Muñoz Prosun Bhattacharya Israel Quino Jorge Quintanilla Ondra Sracek Roger Thunvik Jochen Bundschuh Maria Eugenia García 《Environmental Earth Sciences》2012,66(3):793-807
Water management in semiarid and arid catchments such as the Poopó Lake Basin requires improved understanding of the complex behavior of the various contaminants, which affect the drinking water quality and considered as crucial for sustainable development of the region. Mechanisms of arsenic (As) release in the surface and groundwater were studied. Hydrochemical data for surface water (4 samples) and groundwater (28 samples) were collected in a small watershed in the Poopó catchment at the highland of the Bolivian Andes (Altiplano). All of them show high electrical conductivity values and moderately oxidizing conditions. The surface water contains high concentration of sulfate and the trace elements As, Zn and Pb in the zone affected by acid mine drainage. There is a large variability of the concentration of As and of the trace elements in the groundwater in the five different regions within the Poopó catchment. The metal concentrations sensitive to changes of redox state and results of speciation modeling suggest that As (V) is a predominant aqueous species, which conforms to the prevailing oxidizing conditions in the shallow groundwater environment. Two generalized trends for As distribution were identified in groundwater: (a) high concentrations are found in the arid zone (100–250 μg/L) in the southern (region III) and in the northwestern (region V) regions, and (b) low concentrations (<50 μg/L) are found in the remaining part of the basin (region I, II and IV). However, the spatial distribution within these regions needs to be investigated further. A conclusion from the present study is that there are multiple sources of As as well as other trace elements (such as Cd, Mn and Zn) in the Poopó Lake Basin. Among the sources and the processes which led to the mobility of As and other trace metals in the region are: (a) weathering of sulfide minerals, (b) oxidation of pyrite and/or arsenopyrite in mineralized areas and (c) desorption from hydrous ferric oxide (HFO) surfaces. In non-mining areas, volcanic ash is suggested to be a significant source of As. 相似文献
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Oswaldo Siga Leonardo Fadel Cury Ian McReath Ligia Maria de Almeida Leite Ribeiro Kei Sato Miguel Ângelo Stipp Basei Cláudia Regina Passarelli 《Gondwana Research》2011,19(1):260-274
The results of geological mapping, chemical analysis and radiometric dating of metabasic rocks of Betara Formation, and mapping and dating of those present in the Betara basement nucleus together with mylonitic granodiorite and syenogranite are reported here. U–Pb analysis of bulk zircon fractions from the metabasic rocks of the basement nucleus yielded a Statherian age of 1790 ± 22 Ma, while the metabasic rocks from the upper part of the Betara Formation yielded a Calymmian age between 1500 and 1450 Ma. This age is a minimum for the deposition of the Betara Formation. The older metabasic rocks are associated with post-tectonic, possibly anorogenic syenogranite, while the younger ones are gabbro or very porphyritic ankaramite whose REE patterns are consistent with crystallization from an N-MORB parent magma. The observations and data point to the probable events associated with extensional processes of the end of Paleoproterozoic and early Mesoproterozoic. Similar registers of Statherian (1.80–1.75 Ga) and Calymmian (1.50–1.45 Ga) extensional events are recorded in other parts of the South American and African continents. The Neoproterozoic witnessed the formation and junction of the tectonic slices which formed the Apiaí domain during the assemblage of western Gondwana. 相似文献
8.
Sandra R. Oliveira Oswaldo D. Miranda & José C. N. de Araujo Reuven Opher 《Monthly notices of the Royal Astronomical Society》1998,301(1):115-130
In this article we extend the study performed in our previous article of the collapse of primordial objects. We here analyse the behaviour of the physical parameters for clouds ranging from 107 to 1015 M⊙ . We study the dynamical evolution of these clouds in two ways: as purely baryonic clouds and as clouds with non-baryonic dark matter included. We start the calculations at the beginning of the recombination era, following the evolution of the structure until the collapse (which we defined as the time when the density contrast of the baryonic matter is greater than 104 ). We analyse the behaviour of several physical parameters of the clouds (e.g. the density contrast and the velocities of the baryonic matter and the dark matter) as a function of time and radial position in the cloud. In this study all physical processes that are relevant to the dynamical evolution of the primordial clouds, such as for example photon drag (due to the cosmic background radiation) and hydrogen molecular production, besides the expansion of the Universe, are included in the calculations. In particular we find that the clouds with dark matter collapse at higher redshift when we compare the results with the purely baryonic models. As a general result we find that the distribution of the non-baryonic dark matter is more concentrated than the baryonic one. It is important to stress that we do not take into account the putative virialization of the non-baryonic dark matter; we just follow the time and spatial evolution of the cloud, solving its hydrodynamical equations. We also studied the role of cooling–heating processes in the purely baryonic clouds. 相似文献
9.
Wang Qing Yamaguchi Ryan T. Kalogiros John A. Daniels Zachary Alappattu Denny P. Jonsson Haflidi Alvarenga Oswaldo Olson Alex Wauer Benjamin J. Ortiz-Suslow David G. Fernando Harindra Joseph 《Boundary-Layer Meteorology》2021,181(2-3):267-292
Boundary-Layer Meteorology - A total of 15 fog events from two field campaigns are investigated: the High Energy Laser in Fog (HELFOG) project (central California) and the Toward Improving Coastal... 相似文献
10.
Rodriguez Fabian Toulkeridis Theofilos Sandoval Washington Padilla Oswaldo Mato Fernando 《Natural Hazards》2017,85(1):605-618
Natural Hazards - The Cotopaxi volcano in north-central Ecuador is one of the most dangerous volcanoes of the world due to its ability to generate far-reaching lahars, which are able to destroy... 相似文献