Geophysical mapping by very low frequencies method and drilling survey in the vicinity of the Hranická Chasm (Hranice Karst)
Vol.14,(2007)
Abstract
Keywords:
Hranice karst; karst sediment; geophysical measurement; very low frequencies
The geophysical method of Very Low Frequencies (VLF) was applied to find conductive zones in the depths between 30 and 60 meters in the surrounding of Hranická propast abyss. Such conductive zones occur along the faults or tectonic lines or crevices with sediments especially close to the underground water level. They can represent corrosive caves in the hydrothermal karst that is typical for Hranice karst. In the area of 12 ha in the surrounding of Hranická propast abyss there were found 3 main conductive zones (B1, B2, B3) in the direction of approx. 90° (E-W) and one zone (A) in the direction approx. 110–120° which is crossing the abyss. The pilot drilling was unsuccessful, no concrete karst objects were discovered. The sample taken from borehole cores had only redeposited flysh fossils, not show qualification of dating of sediments.
Hranice karst; karst sediment; geophysical measurement; very low frequencies
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