The potential use of geophysical methods to identify cavities, sinkholes
and pathways for water infiltration: a case study from Mambaí, Brazil
Yawar Hussain
Environmental Engineering and Earth Science Department, Clemson University, Clemson, SC, United States, Environmental Engineering and Earth Science Department, Clemson University, Clemson, SC, United States
Corresponding Author:[email protected]
Author ProfileAbstract
The use of geophysical characterization of karst systems can provide an
economical and non-invasive alternative for extracting information about
cavities, sinkholes, pathways for water infiltration as well as the
degree of karstification of underlying carbonate rocks. In the present
study, three geophysical techniques, namely, Ground Penetrating Radar
(GPR), Electrical Resistivity Tomography (ERT) and Very Low Frequency
Electromagnetic (VLFEM) were applied at three different and appropriate
locations in fluvial karst of a listed environmentally sensitive area of
the Rio Vermelho, Mambaí, Goiás, Brazil. In the data acquisition phase,
the GPR, direct-current (DC) resistivity and VLFEM profiles were
obtained at three different locations in the area. Data were analyzed
using commonly adopted processing workflows. Different radar typologies
have been assigned to soil and rock typse. The GPR results showed a
well-defined lithology of the site based on the amplitude of the signal.
On the other hand, the inverted resistivity cross-sections showed a
three-layered stratigraphy, pathways of water infiltration and the
weathered structures in carbonate (Bambui group). The interpretation of
VLFEM as contours of current density resulted from Fraser and
Karous-Hjelt filters, indicate the presence of conductive structures
(high apparent current density) that may be linked with the weathered
carbonate and other conductive and resistive anomalies may be associated
with the water-filled and dry cavities (cave). The results encourage the
integrated application of geophysical techniques as the reconnaissance
for further detailed characterization of the karst areas.