Social vulnerability assessment to seismic risk using multicriteria analysis: the case study of Vila Franca do Campo (S?o Miguel Island, Azores, Portugal)

The increase in the frequency and magnitude of disasters triggered by earthquakes in different regions of the Earth is a major challenge to contemporary societies. The awareness that disasters and risk are processes structured on spatial?Ctemporal interactions maintained at the social-ecological system between the natural hazards and the vulnerabilities of socioeconomic, political and physical nature becomes utterly important in the increase of social systems?? resilience. Thus, the assessment of social vulnerability plays a decisive role in understanding the factors that distinguishes individuals, households and communities, in terms of their ability to anticipate, cope with, resist to and recover from the impact of disasters triggered by natural hazards. This article presents a geographic information system (GIS)-based approach model to assess the social vulnerability to seismic risk using multicriteria analysis (MCA) techniques, in a group decision-making process. The methodology applied to the municipality of Vila Franca do Campo (S?o Miguel Island, Azores, Portugal) identified moderate social vulnerability values at the neighbourhood level and higher social vulnerability values for the built environment and demographic characteristics of the social groups. The social vulnerability patterns make a clear distinction between the older/historical urban cores and the new urban areas. In the first case, the presence of ancient buildings constructed with materials of low resistance to earthquakes coupled with a higher population density and the traits of demographic and socioeconomic frailties of the social groups, results in higher vulnerability values. This pattern is common in the historic centre of S. Miguel district, Ribeira das Taínhas, northern areas of água de Alto and western and eastern neighbourhoods of Ponta Gar?a. The new urban areas, mainly found in S. Pedro, central areas of água de Alto, S. Miguel and Ponta Gar?a districts, have lower values of social vulnerability due to changes in the built, demographic and socioeconomic environments. Results recommend the integration of social vulnerability indexes into seismic risk mitigation policies and emergency management planning.     

Juvenile contribution of the Neoproterozoic Rio Negro Magmatic Arc (Ribeira Belt,Brazil): Implications for Western Gondwana amalgamation

The ca. 790–600 Ma Rio Negro Complex (RNC) of the Ribeira belt (Brazil) consists of a plutonic portion of a magmatic arc built by the E-vergent subduction of the ESE border of the São Francisco paleoplate during the amalgamation of Western Gondwana.The plutonic series comprises low- to medium-K granitoids (ca. 790–620 Ma) and high-K granitoids and shoshonite rocks (ca. 610–605). The age span of 185 m.y. is suggestive of a long history of arc-related magmatism, continuously or not in time. The Nd isotopic signatures of the RNC consist of εNd(t) ratios from ? 3 to + 5 for the medium-K series shoshonite series and from ? 14 to ? 3 for the younger high-K group. This time-dependent trend of Nd isotopes is indicative of progressive maturity of the arc over time. The same evolution is indicated by Sr data, as the medium-K rocks have ⁸⁷Sr/⁸⁶Sr initial ratios < 0.705 while the high-K rocks yield values between 0.705 and 0.710. The predominance of intermediate rocks over mafic ones suggests an initial intra-oceanic to transitional stage, possibly developed in a distal portion of a passive margin, such as the Japanese arc, evolving to a more developed, differentiated felsic rock associations.The role of transform fault zones, such as the Luanda shear zone, is emphasized in order to explain the consumption of a wide oceanic plate in the inner portion of Western Gondwana.     

Geoelectrical mapping of contamination in the cemeteries: the case study in Piracicaba,São Paulo/Brazil

This paper presents the results of electrical resistivity methods in the area delineation that was potentially contaminated by liquefaction products, which are also called putrefactive liquids in Vila Rezende municipal cemetery, Piracicaba, São Paulo, Brazil. The results indicate a depth of water table between 3.1 and 5.1 m, with two groundwater direction flows, one to the SW and another to the SE. Due to the contamination plumes, which have the same groundwater direction flow, as well the conductive anomalies observed in the geoelectric sections, the contamination suspicions in the area were confirmed. The probable plume to the SE extends beyond the limits of the cemetery. The location of the conductive anomalies and the probable contamination plumes showed that the contamination is linked with the depth of the water table and the burial time. Mapping using the geostatistical method of ordinary kriging applied to the work drew structural characteristics of the regional phenomenon and spatial behavior of the electrical resistivity data, resulting in continued surfaces. Thus, this method has proved to be an important tool for mapping contamination plumes in cemeteries.     

Influence of the properties of tropical soils in the toxicity and bioavailability of heavy metals in sewage sludge-amended lands

The toxicity and potential bioavailability of heavy metals were studied in sewage sludge-amended ferralsols and chernosols, using bioassays with earthworms (Eisenia andrei). Acute toxicity tests and avoidance assays were performed according to standard protocols. Potentially bioavailable concentrations of heavy metals were estimated by quantifying their concentrations in tissues of survival earthworms. The results revealed that soil properties played an important role in the toxicity and bioavailability of heavy metals. In this respect, higher levels of toxicity were detected for the ferralsol. The abundance of 2:1 clay minerals, high fertility and more basic values of pH seem to be very important in the reduction of toxicity levels for earthworms. Organisms exposed to the chernosols were able to uptake higher amount of metals. In that case, higher contents of nutrients in chernosols may have influenced such bioavailability processes. Avoidance responses were the most sensible indicator of toxicity. In the near future, such data can subsidize the establishment of toxic reference concentrations able to reflect the characteristics of important tropical pedological occurrences, supporting the definition of sustainable indicators for using sewage sludge in the tropical agriculture.     

Dip‐adaptive singular‐value decomposition filtering for seismic reflection enhancement

We present a singular value decomposition (SVD) filtering method for the enhancement of coherent reflections and for attenuation of noise. The method is applied in two steps. First normal move‐out (NMO) correction is applied to shot or CMP records, with the purpose of flattening the reflections. We use a spatial SVD filter with a short sliding window to enhance coherent horizontal events. Then the data are sorted in common‐offset panels and the local dip is estimated for each panel. The next SVD filtering is performed on a small number of traces and a small number of time samples centred around the output sample position. Data in a local window are corrected for linear moveout corresponding to the dips before SVD. At the central time sample position, we sum over the dominant eigenimages of a few traces, corresponding to SVD dip filtering. We illustrate the method using land seismic data from the Tacutu basin, located in the north‐east of Brazil. The results show that the proposed method is effective and is able to reveal reflections masked by ground‐roll and other types of noise.     

Producing time series of river water height by means of satellite radar altimetry—a comparative study

Abstract

Satellite radar altimetry is complementary to in situ limnimetric surveys as a means of estimating the water height of large rivers, lakes and flood plains. Production of water height time series by satellite radar altimetry technology requires first the selection of radar ground target locations corresponding to water body surfaces under study, i.e. the definition of “virtual limnimetric stations”. We propose to investigate qualitative and quantitative differences between three representative virtual station creation methodologies: (a) a fully manual method, (b) a semi-automatic method based on a land cover characterization that allows the water body surface under study to be located; and (c) an original fully automatic procedure that exploits a digital elevation model and an estimation of the river width. The results yielded by these three methods are comparable: maximum absolute magnitudes of water height differences being 0.46, 0.26 and 0.15 m for, respectively, 95, 90 and 80% of the water height values obtained. Moreover, more than 67% and 92% of time series jointly produced by the methods present root mean square differences lower than 20 and 50 cm, respectively. The results show that the fully automatic method developed herein provides as reliable results as the fully manual one. This opens the way to use of satellite radar altimetry for the generation of water height time series on a large scale, and considerably extends the applicability of satellite radar altimetry in hydrology.

Citation Roux, E., Santos da Silva, J., Vieira Getirana, A. C., Bonnet, M.-P., Calmant, S., Martinez, J.-M. & Seyler, F. (2010) Producing time series of river water height by means of satellite radar altimetry—comparative study. Hydrol. Sci. J. 55(1), 104–120.     

Comment

Résumé

Les observations tensiométriques et piézométriques au voisinage du ruisseau des Maurets, dans le bassin du Réal Collobrier, fournissent des informations intéressantes sur les mécanismes hydrologiques en cas de crue. Des mesures au pas de temps hebdomadaire montrent une bonne corrélation entre le débit dans la rivière et le niveau piézométrique au voisinage de celle-ci. D'autre part, on observe que ce niveau ne peut monter que si la pression d'eau dans le sol avant la crue est voisines de zéro. D'autres observations tensiométriques plus détaillées ont été effectuées au pas de temps de la demi-heure. Elles montrent que seules les pluies de fortes intensités peuvent provoquer une montée rapide de la pression positive d'eau du sol (saturation), à condition que cette pression soit très voisine de zéro avant la pluie. Dans ce cas, le gradient vertical de la charge hydraulique est quasi-nul, et des zones saturées contributives apparaissent et se développent, accompagnées de forts débits de crue dans la rivière. Ainsi, même dans des conditions méditerranéennes, les crues peuvent être provoquées par le développement des surfaces saturées contributives au voisinage des rivières. Dans ce cas, sur le bassin étudié, ces surfaces saturées ont une durée de vie très courte.     

Air–Sea Interaction Processes Influencing the Development of A Shapiro–Keyser Type Cyclone over the Subtropical South Atlantic Ocean

This study analyzes the impacts of latent and sensible heat exchanges between the atmosphere and the ocean in a non-explosive Shapiro–Keyser type cyclogenesis event that occurred over the southwestern South Atlantic Ocean. The synoptic evolution shows a relatively strong warm front and a cold frontal fracture during the system’s development and a warm seclusion in its mature stage, characterizing a Shapiro–Keyser type cyclone. Numerical experiments with the ARW-WRF Model version 3.3 were used to investigate the influences of sensible and latent fluxes on the track of the surface low, intensity of the fronts and coupling of the lower and upper troposphere. The simulations indicate that in the presence of these fluxes the cyclone underwent greater intensification, had a longer life time and longer trajectory, and presented a typical southeastward movement. In the absence of these fluxes, the cyclone developed a weaker warm front with consequent reduction of diabatic heating due to grid scale precipitation along it. This reduced the negative pressure tendency southeast of the cyclone center and the surface cyclone moved northeastward, showing a decoupling of the lower- and upper-level waves. A consequence of this anomalous tracking is the location of the surface cyclone beneath the upper-level trough axis, where there is no upper-level divergence associated with cyclonic vorticity advection contributing to the further system intensification. Numerical experiments suggest that for this Shapiro–Keyser type cyclone the air–sea interaction processes are crucial to obtain a cyclone with features similar to the observations.     

The consequences of Brazil’s lack of transport planning is written in the blood of sparrows

The medium-sized cities of Brazil are those with populations of between 100,000 and 500,000 inhabitants. These cities are growing rapidly, and are characterized by poor urban planning, a loss of biodiversity and decreasing health prospects for residents. Historically, urbanization in Brazil has been associated with incentives to increase the use of private vehicles for local transport. The air pollution resulting from this “car dependency” has been quantified in some major cities in Brazil, such as the megacity of São Paulo. In this paper, we demonstrate through a bioindication study carried out in the Brazilian city of Rondonópolis, that atmospheric pollution resulting from vehicular emissions is also a measurable reality for medium-sized cities. Most Brazilian cities lack air quality measurement equipment, and we used an inexpensive and easy to apply bioindication assay to measure air pollution, and this approach could be easily implemented in those cities and beyond.     

Paying as the urban areas grow – implementing and managing urban development charges using a GIS application

Urban development charges (UDC) are considered relevant taxation instruments that can improve the economic sustainability of urban areas and the financial health of the respective local governments. The economic formulation and justification based on the ‘direct benefit principle,’ the ‘accountability principle,’ and the ‘proportionality principle’ requires a methodology that can be supported by a geographic information system (GIS) application. This article presents the research output of a real case study – the municipality of Aljezur, Portugal – and the fundamentals of the GIS tool that was designed. This GIS-based methodology comprises a multi-annual infrastructure capital plan and an accurate zoning map for spatial differentiation of values combining municipal-wide and site-specific approaches, following ‘pay as the urban areas grow’ perspective applied to urban development and new buildings. It requires data integration of the urban planning process with infrastructure and urban growth data in order to manage and monitor the computation of this charge over time, thereby increasing the accuracy, the objectivity and the clarity of the process. The results obtained show that this UDC-GIS application seems well adapted to small municipalities. Its possible replication and use in other contexts require adaptations derived from different urban and taxation policy options and from different legal, organizational, technological, and informational local systems.