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1.
The use of GPR and VES in delineating a contamination plume in a landfill site: a case study in SE Brazil 总被引：3，自引：0，他引：3
Jorge L. Porsani Walter M. Filho Vagner R. Elis Fisseha Shimeles Joo C. Dourado Helyelson P. Moura 《Journal of Applied Geophysics》2004,55(3-4):199-209
This paper presents the results of the application of the Ground Penetrating Radar (GPR) method, or Georadar, in outlining a zone of contamination due to solid residues at the waste burial site of Rio Claro in the state of São Paulo, SE Brazil. A total of eight GPR profiles with 50- and 100-MHz antennae were surveyed. Six profiles were located within the landfill site and the remaining two were outside. The main objective of the GPR survey was to evaluate the side extension of contamination. A Vertical Electric Sounding (VES) survey was performed at four points within the site in order to investigate the vertical extent of the contamination plume and to define the bottom of the landfill. Two additional VESs were done outside the landfill with the purpose of determining the top of the ground water table and the geoelectric stratigraphy of the background. From the interpretation of the GPR profiles, it was possible to locate the top of the contamination plume and to infer that it was migrating laterally beyond the limits of the waste disposal site. This was observed along the profile situated close to the highway SP-127, which was about 20 m from the limit of the site. The signature of the contaminant appears as a discontinuous reflector that is believed to be a shallow ground water table. The discontinuity is marked by a shadow zone, which is characteristic of conductive contaminant residues. The contamination did not move far enough to reach a sugar cane plantation located at approximately 100 m from the border of the site. In the regions free from contamination, the ground water table was mapped at approximately 10 m of depth, and it was characterized by a strong and continuous reflector. The radar signal penetrated deep enough and enabled the identification of a second reflector at approximately 14 m deep, interpreted as the contact between the Rio Claro and the Corumbataí formations. The contact is marked by the presence of gravel characterized by ferruginous concretes, which cause the strong amplitude reflection in the GPR profile. Within the landfill site, the quantitative interpretation of the VES results showed the contamination zone. The base of the landfill varies between 11 and 15 m deep. Outside the landfill site, the VES results showed no indication of contamination and allowed the determination of the top of the ground water table and the contact between the Rio Claro and the Corumbataí formations. The results of GPR and VES showed a good agreement and the integrated interpretations were supported by local geology and information from several boreholes, about 17 m depth, on average. The bottom of the landfill reaches a maximum of 14.5 m depth. 相似文献
2.
Summary A local planar approximation of a stratified, inhomogeneous, anisotropic and dissipative ionosphere is presented as an Alfven
quarter-wave plate resonator in the Pc1 micropulsation range. The frequency-amplitude structure of the resonance response
of an isotropic Alfven wave on the Earth's surface and at a given altitude in the ionosphere is studied in comparison to standing
waves in vacuum above an ideal conductor for a particular model of the ionosphere. An asymmetry in the response was found
at both boundary of the resonator, at the Earth's surface and at the given altitude z0. The results are related to the vertical changes of frequency dispersion in the dissipative medium of the ionosphere and
to the vertical profile of the inhomogeneities of the resonator being considered. 相似文献
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Alexandre Lisboa Lago Vagner Roberto Elis Welitom Rodrigues Borges Giovanni Chaves Penner 《Environmental Geology》2009,58(2):407-417
Geophysics has been shown to be effective in identifying areas contaminated by waste disposal, contributing to the greater efficiency of soundings programs and the installation of monitoring wells. In the study area, four trenches were constructed with a total volume of about 25,000 m3. They were almost totally filled with re-refined lubricating oil waste for approximately 25 years. No protection liners were used in the bottoms and laterals of the disposal trenches. The purpose of this work is to evaluate the potential of the resistivity and ground penetrating radar (GPR) methods in characterizing the contamination of this lubricant oil waste disposal area in Ribeirão Preto, SP, situated on the geological domain of the basalt spills of the Serra Geral Formation and the sandstones of the Botucatu Formation. Geophysical results were shown in 2D profiles. The geophysical methods used enabled the identification of geophysical anomalies, which characterized the contamination produced by the trenches filled with lubricant oil waste. Conductive anomalies (smaller than 185 Ωm) immediately below the trenches suggest the action of bacteria in the hydrocarbons, as has been observed in several sites contaminated by hydrocarbons in previously reported cases in the literature. It was also possible to define the geometry of the trenches, as evidenced by the GPR method. Direct sampling (chemical analysis of the soil and the water in the monitoring well) confirmed the contamination. In the soil analysis, low concentrations of several polycyclic aromatic hydrocarbons (PAHs) were found, mainly naphthalene and phenanthrene. In the water samples, an analysis verified contamination of the groundwater by lead (Pb). The geophysical methods used in the investigation provided an excellent tool for environmental characterization in this study of a lubricant oil waste disposal area, and could be applied in the study of similar areas. 相似文献
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Space-borne geodetic sensors and model-based datasets have been used to monitor groundwater changes in the Yangtze River basin (YRB). Groundwater storage variations were computed using the following datasets:? Gravity Recovery and Climate Experiment (GRACE)-derived terrestrial water storage (TWS),? Noah driven Global Land Data Assimilation System (GLDAS-Noah) model to simulate the total water content (TWC) i.e. soil moisture, ice and snow, and canopy water storage, and? Satellite altimetry-observed surface water reservoir storages.Overall, the results show that groundwater in the YRB rose by at least 3.34 km3/yr between January 2003 and December 2009. However, the estimated groundwater linear trend for the period of 2003–2009 was ?0.95 km3/yr according to the Changjiang and Southwest Rivers Water Resource Bulletin (CJSRWB). An analysis of the methodology of the CJSRWB shows that the groundwater estimate was based on the water balance approach, which has been found to be weak in inter-basin sub-surface flow. The GRACE-estimated groundwater rise is larger and suggests that the YRB is affected by seepage from Tibetan lakes through a sub-surface fault. Additionally, there is evidence showing that water loss from the Yangtze River by underground leakage through faults could also be a cause of the difference. Therefore, it is concluded that further investigation is required to determine the causation. 相似文献
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Karel Prikner Vladimír Vagner Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1988,32(1):84-100
Summary The method of numerical modelling of ionospheric filtration of the Fourier components of a signal from the frequency range of Pc1 micropulsations is employed in the spectral analysis (frequency f, angle of incidence ) of the relative characteristic of the amplitude and energy reflectivity of the ionospheric layer with respect to ordinary Alfvén modes incident in the meridional plane. The results are presented for four different models characterizing the midlatitude day- and night-time ionosphere under low and high solar activity. The results indicate the specificity of filtration of ordinary Alfvén waves. It is proved that the lower region of the modelled ionosphere, as part of the midlatitude ionospheric wave guide (in particular the F2 layer), behaves like an Alfvén resonator in the given spectral range.
m¶rt; u ¶rt;uau u umauu -mau uaa u amm ¶rt;uanaa unau 1 n¶rtum nma aau (amma f, a¶rt;u ) mum anum¶rt; u mu maamu u ¶rt; ¶rt; a, a¶rt;au a u u¶rt;ua nmu. mam n¶rt;aam ¶rt; m a ¶rt; ¶rt;um m ¶rt; u u nu u u nu amumu. aam nuum umauu a. naa, m ua am ¶rt;ua u (a am F2-u ¶rt;um ¶rt;a) ¶rt;m nma ¶rt;uana a am a.相似文献
9.
Karel Prikner Vladimír Vagner Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1985,29(3):269-279
Summary The vertical distribution of the contribution of the energy flux density due to the Alfvén(ordinary) wave, guided by the geomagnetic field(and propagating through the ionosphere to the Earth's surface) in the horizontal direction is demonstrated in the mechanism of the horizontal propagation of the Pc1 signal. The distribution with height is shown of the variations of the polarization characteristics of the propagating wave(e.g. the rotation of the polarization plane, changes in ellipticity, attenuation, etc.), which are the result of coupling in the denser layers of the low ionosphere in which also suitable isotropic(extraordinary) modes are generated. The results obtained using the method described in[4, 13] are demonstrated on a model of the daytime ionosphere under incidence of ordinaryL-modes, frequency f=0.3 Hz, and various meridional angles at the ionosphere.
auauma anmau uaa Pc1 naa m an¶rt;u ¶rt;u nmmu ma uu uma anauu maum n n¶rt; , anma u nmu. naa m an¶rt;u uu aamumu nuauu anma (nauau nmu nuauu, uu unmumu, amau u m.¶rt;.), m m ¶rt;mu au¶rt;mu na uu u . ¶rt; mum n¶rt;¶rt;u umn() ¶rt;. mam num m¶rt; [4, 13] ¶rt;mua ¶rt;u ¶rt; u nu na¶rt;uu a u L-¶rt; amm f=0,3 n¶rt; au u¶rt;uau au.相似文献
10.
Geoenvironmental site investigation using different techniques in a municipal solid waste disposal site in Brazil 总被引：3，自引：0，他引：3
Giulliana Mondelli Heraldo Luiz Giacheti Maria Eugênia Gimenez Boscov Vagner Roberto Elis Jorge Hamada 《Environmental Geology》2007,52(5):871-887
Different geoenvironmental site investigation techniques to assess contamination from a municipal solid waste disposal site
in Brazil are presented here. Superficial geophysical investigation (geoelectrical survey), resistivity piezocone penetration
tests (RCPTU), soil samples collected with direct-push samplers and water samples collected from monitoring wells were applied
in this study. The application of the geoelectrical method was indispensable to identify the presence and flow direction of
contamination plumes (leachate) as well as to indicate the most suitable locations for RCPTU tests and soil and water sampling.
Chemical analyses of groundwater samples contributed to a better understanding of the flow of the contaminated plume. The
piezocone presented some limitations for tropical soils, since the groundwater level is sometimes deeper than the layer which
is impenetrable to the cone, and the soil genesis and unsaturated conditions affect soil behavior. The combined interpretation
of geoelectrical measurements and soil and water samplings underpinned the interpretation of RCPTU tests. The interpretation
of all the test results indicates that the contamination plume has already overreached the landfill’s west-northwest borders.
Geoenvironmental laboratory test results suggest that contamination from the solid waste disposal site has been developing
gradually, indicating the need for continuous monitoring of the groundwater. 相似文献