2012
Autores
Moura, R; Noronha, F; dal Moro, G; Umaraliev, R;
Publicação
12TH INTERNATIONAL MULTIDISCIPLINARY SCIENTIFIC GEOCONFERENCE, SGEM 2012, VOL. II
Abstract
The measurement of shear wave velocity (Vs) is an established approach in contributing to earthquake site response. Currently, in terms of sensors, horizontal geophones have been added as an option to the more common vertical geophones and thus being able to measure Love waves. In terms of processing the most recent development has been the possibility of joint inversion of data sets of different types (Rayleigh+Love, Rayleigh+HVSR, Rayleigh+Refraction). Since some of most important earthquake site response measurements have to be performed in urban environments this can pose a problem to the in situ measurements due to the lower signal to noise ratio. Thus we aim to show a case study of results of dispersive wave tests, made in the urban environment of the city Porto in Northern Portugal, with the objective of contributing towards a microzoning GIS map that we are currently engaged in improving. Porto is set in a crystalline environment with a rock mass that is variably weathered thus our test results will be compared with the geotechnical map of Porto.
2011
Autores
Fontoura, MJ; Lino, FJ; Ribeiro, SP; Rios, SM; Moura, RM; Dias, AG;
Publicação
Near Surface 2011 - 17th European Meeting of Environmental and Engineering Geophysics
Abstract
The assessment of contaminants dispersion in Controlled Dumps (CD) of Municipal Solid Waste (MSW) is possible through the combination of geophysical, geochemical and geostatistical methods as described in this paper. The methodology applied in this study will contribute to evaluate the environmental consequences of the Matosinhos CD (N Portugal), which is set in a granitic crystalline geological context with a permeability controlled by differential weathering associated with fracturing. The statistical methods here described (Lepeltier, 1969; Matschullat et al. 2000) are adapted to use in geophysical data obtained from the resistivity profiles performed in the CD surroundings by the electrical resistivity method. Groundwater samples were collected in piezometers; upstream and downstream of the CD, with the aim of directly confirming the presence of contaminants indirectly detected by the geophysical and geostatistical methods. The combination of these different approaches allows an approach to the detection and delineation of contaminant plumes from these deposits.
2007
Autores
Santos, P; Cunha, D; Bastos, C; Lima, A; Moura, R;
Publicação
Near Surface 2007 - 13th European Meeting of Environmental and Engineering Geophysics
Abstract
In the past decades urban areas have suffered large demographic pressures, forcing people and their housing compounds to migrate to peripheral regions were they often build without land planning concerns, and where many times they are subject to adverse natural conditions and exposed to natural hazards being landslides one of the main threats. Nowadays, geophysical methods assume a relevant role monitoring and surveying unstable slopes. We performed thirty seismic profiles with the aim of determine distribution of rock weathering through seismic refraction techniques, in Canelas, a small village in NW Portugal. Each profile was summarized with average values of velocity for each depth. Despite having a low density coverage for the area involved, the results seem to show that seismic refraction is an important tool to rapidly characterize weathering thicknesses, a very important factor to be taken into account in problems of slope stability.
2010
Autores
Granja, H; Rocha, F; Matias, M; Moura, R; Caldas, F; Marques, J; Tareco, H;
Publicação
QUATERNARY INTERNATIONAL
Abstract
The Lagoa da Apulia is a unique feature in the NW coastal zone of Portugal, a remaining form from a lagoon complex system that, during the Late Holocene, was dominant in the region. This system was mainly neotectonically controlled, occupying a depressed area bounded by faults on a Palaeozoic rocky lower platform, today observable on beaches at low tide. With the intention of knowing the main architecture of the palaeo-lagoon, geophysical prospecting with GPR and resistivity was carried out. Accordingly, six cores were taken and the sedimentary and mineralogical facies, and diatom and foraminifer contents were analysed, and five rich organic layers were dated by radiocarbon analysis. With the data, an evolutionary environment reconstruction model was created for this palaeo-lagoon and the main structural features of the neighbouring area.
2012
Autores
Moura, R; Fontoura, MJ; Goncalves, V; Dias, P; Santos, BS; Dias, AG; Marques, JE;
Publicação
Proceedings of the Symposium on the Application of Geophyics to Engineering and Environmental Problems, SAGEEP
Abstract
The assessment of contaminant dispersion in Controlled Dumps (CD) of Municipal Solid Waste (MSW) is possible through the combination of geophysical, geochemical and statistical methods. The methodology applied in this study will contribute to evaluate the environmental consequences of the Matosinhos CD (N Portugal), which is set in a granitic crystalline geological context with a permeability controlled by differential weathering which, in turn, is associated with fracturing. The statistical methods that we will describe are usually used in geochemical anomaly determination and were adapted to be used with resistivity data obtained from twenty-two 2D profiles performed around the CD. The data set was inverted and the results were processed and visualized by a 3D software application that we are currently developing. Groundwater samples were also collected in piezometers, upstream and downstream of the CD, with the aim of directly confirming the presence of contaminants indirectly detected by the geophysical and geostatistical methods described before. The combination of these different approaches allows, in our opinion, an improved approach towards the detection and delineation of contaminant plumes from these deposits.
1995
Autores
Senos Matias, M; Moura, R; Gomes, P; Teixeira, R;
Publicação
1st EEGS Meeting
Abstract
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