Considerations about the occurrence of pollen grains of the Valeriana eichleriana (C.A.Muller) Graebner, in sediments of the Upper Quaternary in the state of Rio Grande do Sul, Brazil     

Paulo C.P.Neves  Soraia G.Bauermann  Maria G.Rossoni  Jose R.R.Coiro  Marleni M.Toigo  Abdul R.Ashraf 《世界地质(英文版)》2004,7(1)

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Seismic vulnerability assessment and characterisation of the buildings on Faial Island, Azores     

Filipe Neves  Aníbal Costa  Romeu Vicente  C. Sousa Oliveira  Humberto Varum 《Bulletin of Earthquake Engineering》2012,10(1):27-44

The earthquake of the 9th of July 1998 that hit in the central group of the Azores archipelago greatly affected the islands of Faial, Pico and S?o Jorge, reaching a magnitude of Mw 6.2 with the epicentre located about 15km northeast of the Faial Island. This earthquake allowed the collection of an unprecedented quantity of data concerning the characterisation of the building stock and the damage suffered by construction. This is the main purpose of this research, consisting essentially of three main aspects: (i) A detailed characterisation of the building stock, assigning a five category classification, from old traditional rubble stone masonry to reinforced concrete moment framed buildings; (ii) A detailed damage grade classification based on the different damage mechanisms observed; and, (iii) A seismic vulnerability assessment of the building stock. The results of the vulnerability assessment together with the building stock database and damage classification were integrated into a GIS tool, allowing the spatial visualation of damage scenarios, which is potentially useful for the planning of emergency response strategies and retrofitting priorities to mitigate and manage seismic risk.  相似文献   

Influence of tide and waves on water renewal in Óbidos Lagoon, Portugal     

Madalena S. Malhadas  Ramiro J. Neves  Paulo C. Leitão  Adélio Silva 《Ocean Dynamics》2010,60(1):41-55

The role of oceanic tide, wind stress, freshwater river inflows, and waves in the long-term circulation and residence time in óbidos Lagoon is investigated using a sensitivity analysis carried out by means of a two-dimensional model. MOHID modeling system coupled to Steady-State Spectral Wave model for simulate óbidos Lagoon circulation were implemented. For residence time calculus, a Lagrangian transport model was used. Tidal forcing is shown to be the dominant forcing, although storm waves must be considered to simulate accurately the long-term circulation. Tidal forcing enhances a spatial distribution in water residence time. Renewal time scales varies from values of 2 days in the near-ocean areas and 3 weeks in the inner areas. Freshwater river inflows decrease the residence time, while waves increase. In heavy rain periods, the water residence time decreases by about 40% in the upper lagoon. When wave forcing is considered, the residence time increases between 10% and 50% depending on lagoon area. The increase in residence time is explained by the sea level rise within lagoon (~1 m above average lagoon sea level) during storm wave periods. Average residence time is 16 days for tidal forcing, 9 days when the rivers are included (wet period), and 18 days when the waves are considered.  相似文献   

Assessing Seismic Damage Through Stochastic Simulation of Ground Shaking: The Case of the 1998 Faial Earthquake (Azores Islands)   总被引：2，自引：0，他引：2  

G. Zonno  C. S. Oliveira  M. A. Ferreira  G. Musacchio  F. Meroni  F. Mota-de-Sá  F. Neves 《Surveys in Geophysics》2010,31(3):361-381

In July 1998, an M _w = 6.2 earthquake struck the islands of Faial, Pico and San Jorge (in the Azores Archipelago), registering VIII on the Modified Mercalli Intensity scale and causing major destruction in the northeastern part of Faial. The main shock was located offshore, 8 km North East of the island, and it triggered a seismic sequence that lasted for several weeks. The existing data for this earthquake include both the general tectonic environment of the region and the teleseismic information. This is accompanied by one strong-motion record obtained 15 km from the epicentre, the epicentre location of aftershocks, and a large collection of the damage inflicted to the building stock (as poor rubble masonry, of 2–3 storeys). The present study was carried out in two steps: first, with a finite-fault stochastic simulation method of ground motion at sites throughout the affected islands, for two possible locations of the rupturing fault and for a large number of combinations of rupture mechanisms (as a parametric analysis); secondly, the damage to buildings was modelled using a well-known macroseismic method that considers the building typologies and their associated vulnerabilities. The main intent was to integrate different data (geological, seismological and building features) to produce a scenario model to reproduce and justify the level of damage generated during the Faial earthquake. Finally, through validation of the results provided by these different approaches, we obtained a complete procedure for the parameters of a first model for the production of seismic damage scenarios for the Azores Islands region.  相似文献   

Optical alteration of complex organics induced by ion irradiation:: 1. Laboratory experiments suggest unusual space weathering trend     

Lyuba Moroz  Giuseppe Baratta  Larissa Starukhina  Maria Antonietta Barucci  Elisa Distefano 《Icarus》2004,170(1):214-228

Most ion irradiation experiments relevant to primitive outer Solar System objects have been performed on ice and silicate targets. Here we present the first ion irradiation experiments performed on natural complex hydrocarbons (asphaltite and kerite). These materials are very dark in the visible and have red-sloped spectra in the visible and near-infrared. They may be comparable in composition and structure to refractory organic solids on the surfaces of primitive outer Solar System objects. We irradiated the samples with 15-400 keV H⁺, N⁺, Ar⁺⁺, and He⁺ ions and measured their reflectance spectra in the range of 0.3-2.5 μm before ion implantation and after each irradiation step. The results show that irradiation-induced carbonization gradually neutralizes the spectral slopes of these red organic solids. This implies a similar space weathering trend for the surfaces of airless bodies optically dominated by spectrally red organic components. The reduction of spectral slope was observed in all experiments. Irradiation with 30 keV protons, which transfers energy to the target mostly via electronic (inelastic) collisions, showed lower efficiency than the heavier ions. We found that spectral alteration in our experiments increased with increasing contribution of nuclear versus electronic energy loss. This implies that nuclear (elastic) energy deposition plays an important role in changing the optical properties of irradiated refractory complex hydrocarbon materials. Finally, our results indicated that temperature variations from 40 K to room temperature did not influence the spectral properties of these complex hydrocarbon solids.  相似文献   

Decay model for biocide treatment of unballasted vessels: application for the Laurentian Great Lakes     

Sano LL  Bartell SM  Landrum PF 《Marine pollution bulletin》2005,50(10):1050-1060

A biocide decay model was developed to assess the potential efficacy and environmental impacts associated with using glutaraldehyde to treat unballasted overseas vessels trading on the Laurentian Great Lakes. The results of Monte Carlo simulations indicate that effective glutaraldehyde concentrations can be maintained for the duration of a vessel's oceanic transit (approximately 9-12 days): During this transit, glutaraldehyde concentrations were predicted to decrease by approximately 10% from initial treatment levels (e.g., 500 mgL(-1)). In terms of environmental impacts, mean glutaraldehyde concentrations released at Duluth-Superior Harbor, MN were predicted to be 100-fold lower than initial treatment concentrations, and ranged from 3.2 mgL(-1) (2 SD: 2.74) in April to 0.7 mgL(-1) (2 SD: 1.28) in August. Sensitivity analyses indicated that the re-ballasting dilution factor was the major variable governing final glutaraldehyde concentrations; however, lake surface temperatures became increasingly important during the warmer summer months.  相似文献   

The 3.4–3.5 Ga São José do Campestre massif, NE Brazil: remnants of the oldest crust in South America     

E. L. Dantas  W. R. Van Schmus  P. C. Hackspacher  A. H. Fetter  B. B. de Brito Neves  U. Cordani  A. P. Nutman  I. S. Williams 《Precambrian Research》2004,130(1-4):113-137

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Holocene dryness and human occupation in Brazil during the “Archaic Gap”     

Astolfo G.M. Araujo  Walter A. Neves  Luís B. Pil  Joo Paulo V. Atui 《Quaternary Research》2005,64(3):298-307

An overview of the archaeological data produced over the last decades for Brazil, coupled with a background of recent paleoenvironmental studies, suggests that during the mid-Holocene vast areas of Central Brazil ceased to be occupied by human groups. Independent data from dated human skeletons, rock-shelter stratigraphy, and chronology of open-air sites converge to support the inference that these areas were depopulated or altogether abandoned. Paleoenvironmental data suggest that dryness events constitute the major cause behind the observed trends. This phenomenon expands the already perceived notion that climatic stresses had a major role in the shaping of human settlement patterns in marginal environments, such as deserts and high-altitude settings.  相似文献   

Consequences of Climate Change on the Ecogeomorphology of Coastal Wetlands     

John W. Day  Robert R. Christian  Donald M. Boesch  Alejandro Yáñez-Arancibia  James Morris  Robert R. Twilley  Larissa Naylor  Linda Schaffner  Court Stevenson 《Estuaries and Coasts》2008,31(3):477-491

Climate impacts on coastal and estuarine systems take many forms and are dependent on the local conditions, including those set by humans. We use a biocomplexity framework to provide a perspective of the consequences of climate change for coastal wetland ecogeomorphology. We concentrate on three dimensions of climate change affects on ecogeomorphology: sea level rise, changes in storm frequency and intensity, and changes in freshwater, sediment, and nutrient inputs. While sea level rise, storms, sedimentation, and changing freshwater input can directly impact coastal and estuarine wetlands, biological processes can modify these physical impacts. Geomorphological changes to coastal and estuarine ecosystems can induce complex outcomes for the biota that are not themselves intuitively obvious because they are mediated by networks of biological interactions. Human impacts on wetlands occur at all scales. At the global scale, humans are altering climate at rapid rates compared to the historical and recent geological record. Climate change can disrupt ecological systems if it occurs at characteristic time scales shorter than ecological system response and causes alterations in ecological function that foster changes in structure or alter functional interactions. Many coastal wetlands can adjust to predicted climate change, but human impacts, in combination with climate change, will significantly affect coastal wetland ecosystems. Management for climate change must strike a balance between that which allows pulsing of materials and energy to the ecosystems and promotes ecosystem goods and services, while protecting human structures and activities. Science-based management depends on a multi-scale understanding of these biocomplex wetland systems. Causation is often associated with multiple factors, considerable variability, feedbacks, and interferences. The impacts of climate change can be detected through monitoring and assessment of historical or geological records. Attribution can be inferred through these in conjunction with experimentation and modeling. A significant challenge to allow wise management of coastal wetlands is to develop observing systems that act at appropriate scales to detect global climate change and its effects in the context of the various local and smaller scale effects.  相似文献   

Does parameterization influence the performance of slope stability model results? A case study in Rio de Janeiro,Brazil     

Carolina de Lima Neves Seefelder  Sérgio Koide  Martin Mergili 《Landslides》2017,14(4):1389-1401

We produce factor of safety (FOS) and slope failure susceptibility index (SFSI) maps for a 4.4-km² study area in Rio de Janeiro, Brazil, in order to explore the sensitivity of the geotechnical and geohydraulic parameterization on the model outcomes. Thereby, we consider parameter spaces instead of combinations of discrete values. SFSI is defined as the fraction of tested parameter combinations within a given space yielding FOS <1. We repeat our physically based calculations for various parameter spaces, employing the infinite slope stability model and the sliding surface model of the software r.slope.stability for testing the geotechnical parameters and the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model (TRIGRS) for testing the geohydraulic parameters. Whilst the results vary considerably in terms of their conservativeness, the ability to reproduce the spatial patterns of the observed landslide release areas is relatively insensitive to the variation of the parameterization as long as there is sufficient pattern in the results. We conclude that landslide susceptibility maps yielded by catchment-scale physically based models should not be interpreted in absolute terms and suggest that efforts to develop better strategies for dealing with the uncertainties in the spatial variation of the key parameters should be given priority in future slope stability modelling efforts.  相似文献