Dissertações em Geofísica (Mestrado) - CPGF/IG

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/4993

O Mestrado Acadêmico pertente a o Programa de Pós-Graduação em Geofísica (CPGF) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA).

Navegar

Navegando Dissertações em Geofísica (Mestrado) - CPGF/IG por Agência de fomento "SUEP/UFPb - Superintendência de Execução de Projetos"

Filtrar resultados informando as primeiras letras
Agora exibindo 1 - 1 de 1
  • Imagem de Miniatura
    ItemAcesso aberto (Open Access)
    Estudo de águas subterrâneas com métodos elétricos na região do semi-árido de Patos - PB
    (Universidade Federal do Pará, 1991-03-21) VITORINO FILHO, Sebastião; BISCHOFF, Jürgen H.
    The Northeast Brazil and the semi-arid region of the State of Paraíba in particular suffers frequent droughts and lack water resources. Surface water does not meet the demand resulting in the search for groundwater as an important item in the development programs of the federal and state governments. In the semi-arid regions occur shallow aquifers and aquifers of fractured crystalline basement rocks. Fractures in crystalline rocks are mostly prospected using aerial photographs and geologic structure studies, resulting in on the average 30% of dry wells among the wells drilled in the region. The alluvial aquifer dimensioning is done by systematic drilling which becomes tedious and expensive in the long run. The objective of this study is to show that geophysical techniques, geoelectrical in particular, are efficient and economical in finding and evaluating areas suitable for groundwater storage in alluvium or crystalline rocks. The traditional resistivity and the less used eletromagnetic methods in groundwater prospecting were applied in this study. For this purpose three semi-arid areas were selected in near the city of Patos, Paraíba, representing two alluvial and one crystalline aquifers. In the case of alluvial aquifers the depth up to the crystalline basement was determined through vertical electrical soundings (VESs) and the lateral limits were mapped through electrical profiling. The results of the VESs are in agreement with the drilling depth values, thus proving the resistivity method as being suitable for study of shallow and narrow alluvial aquifers. In the case of crystalline aquifers a preliminary determination of the general direction of fracture zones was performed through a modified vertical electrical sounding (radial VES). The exact location of these zones was done by electrical and electromagnetic profiling in horizontal loop technique operating with two frequencies of 880 Hz and 2640 Hz. The results of both the methods applied in this study were found to be satisfactory, however, the electromagnetic profiling is faster and requires less manpower, thus, reducing the operating costs in groundwater prospecting in crystalline rocks.
Logo do RepositórioLogo do Repositório