Two sets of probes are typically inserted vertically into the soil one set delivers a current into the soil and the second set measure the voltage differential over some distance i. Electrical resistivity surveys involve inserting electrodes directly into the ground surface and transmitting an electrical current into the soil which acts as a resistive medium. Appendix T : Incorporating boundaries of known layers Appendix U : Special topography information for. GeophysicsĪppendix S : Incorporating data noise estimates. Appendix R : Time-lapse resistivity inversion. ABEM TERRAMETER LS 2Īppendix Q : Bedrock edge detection. Appendix L : Non-conventional or general arrays.Īppendix O : Model refinement. Appendix K : Robust data and model inversion. Appendix I : Cross-borehole data inversion. Appendix G : New batch mode options.Īppendix H : Speed of graphics display. Appendix B : The Wenner-Schlumberger array.Īppendix C : Fixing Resistivities. Appendix A : Dipole-dipole and pole-dipole surveys. Field data will never be perfect, so in order to prepare and optimize the data for the inversion process, noisy and faulty data has to be removed.Temukan segala yang ditawarkan Scribd, termasuk buku dan buku audio dari penerbit-penerbit terkemuka.
Make a note on observations during fieldwork that may have an influence on data quality. Before it is possible to reach the final result in terms of distribution of geological layers, presence of groundwater, depth to the groundwater table or determining the presence of saltwater or not, the data has to pass through a sequence of processing steps.Įverything starts with careful and well documented acquisition of the geophysical raw data. A receiver antenna then measures the rate of the magnetic field's diffusion, which is recalculated to resistivity.Īll data will be collected beneath the same surface position X and Y coordinates but at varying depths Z coordinate. Depending on the positions of the electrodes, the data will be collected at different depths Z coordinate and beneath different surface positions X and Y coordinates. Knowing the injected current and the measured voltage, the Terrameter LS 2 calculates the resistance of the ground. Two electrodes are used to inject a current, and a minimum of two electrodes are used for voltage readings. Our solutions make it possible to identify aquifers and assess their properties and surrounding geology in two ways. If water is contaminated with a pollutant, its electrical properties will change. This makes it possible for us to differentiate between fresh water and saline water. The more saturated with water a material is, the more its resistivity will change.ĭissolved salt has very low electrical resistivity, which means that the higher the salt content of water the lower the resistivity.
Water has low electrical resistivity, lowering the resistivity of most materials in which it is present. All materials have an electrical resistancewhich defines how difficult it is for an electrical current to pass through that material. This is why we need to understand the surrounding geology and how salination zones can spread over time. Through over-use, a borehole connected to such an aquifer can get increasingly mineralized or saline water drawn into it from depth or by lateral pathways. This is why an aquifer can suddenly become polluted, even though no surrounding area seems to be responsible.Īn aquifer that is too close to salt saline water, such as sea water, can be at risk of salination. Gravity will carry pollutants down into the soil and these can be transferred via complex pathways into distant aquifers, causing contamination. An aquifer can be a good source of fresh water for many generations, but it needs to get replenished by a reliable supply. Here, our non-destructive geophysical solutions are both safer and more sustainable. Proper prospecting needs to determine accessibility, longevity, quality, and security of an aquifer.ĭrilling blindly is also ineffective, costly, destructive, and requires lots of energy and heavy equipment. Finding an aquifer that is impractical or unusable will not suffice. This is where our non-destructive solutions give you the upper hand. To find, protect and keep our groundwater deposits aquifers drinkable, we need to not just drill a hole in the ground, but to gain a deeper understanding of potential threats and opportunities. Groundwater is an integral part of life and survival.
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