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ELECTRICAL POTENTIAL (Self-Potential) MEASUREMENTS with LandMapper ERM-02

Self-potential map to detect directions of water fluxes, KievThe self-potential (SP) method was used by Fox as early as 1830 on sulphide veins in a Cornish mine, but the systematic use of the SP and electrical resistivity methods in conventional geophysics dates from about 1920 (Parasnis, 1997). The SP method is based on measuring the natural potential differences, which generally exist between any two points on the ground. These potentials are associated with electrical currents in the soil. Large potentials are generally observed over sulphide and graphite ore bodies, graphitic shale, magnetite, galena, and other electronically highly conducting minerals (usually negative). However, SP anomalies are greatly affected by local geological and topographical conditions. These effects are considered in exploration geophysics as “noise”. The electrical potential anomalies over the highly conducting rock are usually overcome these environmental “noise”, thus, the natural electrical potentials existing in soils are usually not considered in conventional geophysics.

LandMapper ERM-02, equipped with proper non-polarizing electrodes, can be used to measure such “noise” electrical potentials created in soils due to soil-forming process and water/ion movements. The electrical potentials in soils, clays, marls, and other water-saturated and unsaturated sediments can be explained by such phenomena as ionic layers, electro-filtration, pH differences, and electro-osmosis.

Another possible environmental and engineering application of self-potential method is to study subsurface water movement. Measurements of electro-filtration potentials or streaming potentials have been used in USSR to detect water leakage spots on the submerged slopes of earth dams (Semenov, 1980). The application of self-potential method to outline water fluxes in shallow subsurface of urban soils is described in (Pozdnyakova et al., 2001). The detail description of self-potential method procedure is provided in LandMapper manual.

Another important application of LandMapper ERM-02 is measuring electrical potentials between soils and plants. Electrical balance between soil and plants is important for plant health and electrical potential gradient governs water and nutrient uptake by plants. Monitoring of electrical potentials in plants and soils is a cutting-edge research topic in the leading scientific centers around the world.

Locations

Zamboanga 7° 1' 27.3612" N, 122° 11' 20.0544" E
Kiev-Pechersk Lavra Kiev 50° 24' 59.1768" N, 30° 33' 55.836" E

RES2DINV - 2D Geophysical Inversion Software for Resistivity and Induced Polarization data

Supports on land, underwater and cross-borehole surveysRES2DINV with topography

Supports the Wenner (alpha,beta,gamma), Wenner-Schlumberger, pole-pole, pole-dipole, inline dipole-dipole, equatorial dipole-dipole, gradient and non-conventional arrays. 
Supports exact and approximate least-squares optimisation methods 
Supports smooth and sharp constrasts inversions 
Supports up to 16000 electrodes and 21000 data points on computers with 1GB RAM 
Seamless inversion of very long survey lines using sparse inversion techniques 
(RES2DINV only license includes limited used of RES3DINV 3D inversion program)

RES2DINV software is designed to interpolate and interpret field data of electrical geophysical prospecting (2D sounding) of electrical resistivity (conductivity) and induced polarization. The inversion of the resistivity and IP data is conducted by least-square method involving finite-element and finite-difference methods. The software can handle data from any electrode array, including Wenner (a, b, g), dipole-dipole, inline pole-dipole, pole-pole, Wenner-Schlumberger, equatorial pole-dipole and non-conventional arrays. Interpolate data from land, under water, and cross-borehole surveys. Easy data conversion from the most popular geophysical instruments including ABEM  Lund, Syskal, AGI, PASI, IRIS, SCITREX, etc.

Locations

Geotomo Software penang 5° 15' 47.6424" N, 100° 29' 4.6428" E
Landviser, LLC 29° 32' 17.2716" N, 95° 4' 28.9776" W

Mapping Alluvial Soils of Humid Areas with Electrical Geophysical Methods

Valley soils of humid areas are comprised of various peat and sandy soils of alluvial or lacustrine origins. These soils are located in subordinated positions in a landscape and accumulated high amounts of organic matter and mineral nutrients. Fluctuation of the river bed in space often causes highly complex soil cover in a valley. Studying those soils with conventional methods of soil mapping is very time and resource consuming. Therefore, we tested the electrical geophysical methods of non-contact electrical profiling (NEP) and electrical profiling (EP) for mapping peat and mineral alluvial soils formed in the glacial valley of Yachroma river.

The distinction in botanical structure of peat and hydrology conditions at the different zones of the valley causes distinction in physical and chemical properties of sedge-mossy, grass-woody, and mineral-peat layered soils (Figure).  The sedge-mossy peat typically has lower ash content and bulk density, and higher water content, than the grass-woody peat. Electrical resistivity of sedge-mossy peat soil is minimal (<20 ohm m) in comparison with resistivity of grass-woody (30-40 ohm m) and mineral-peat layered soils (50-60 ohm m).

Местоположение

CPBRS Горшково, MOS 56° 22' 30.2448" N, 37° 25' 8.724" E

Electrical Geophysical Methods to Evaluate Soil Pollution from Gas and Oil Mining

transect across bitumen polluted soil and brune collectorElectrical geophysical methods were successfully used for exploration of gas and oil fields (Kalenev, 1970). However, the methods are not widely used for estimation of the soil pollution with petroleum products (Znamensky, 1980; Pozdnyakov et al., 1996a). The possibility of using the methods of electrical resistivity to evaluate the places of petroleum pollution or natural petroleum and gas deposits is based on highly different resistivities of soil and petroleum products. Petroleum and various products of petroleum manufacture, such as oil, gasoline, bitumen, and kerosene have very high electrical resistivity compared with soils. Electrical resistivity of petroleum varies from 104 to 1019 ohm m (Fedinsky, 1967), whereas resistivity of petroleum-saturated sand is much lower (2200 ohm m) (Znamensky, 1980), but is still higher than that of any non-polluted soil.

Soil pollution by the products of gas and petroleum mining was studied near Urengoi in northwest Siberia, Russia. The virgin soils, Glacic and Aquic Haplorthels, were extremely polluted with various by-products of petroleum extraction and manufacturing, such as bitumen, gasoline, kerosene, and mining brine solutions. The study area was thoroughly investigated with four-electrode profiling on 1.2-m array and vertical electrical sounding.

Местоположение

Urengoj 65° 57' 27" N, 78° 23' 4.2" E

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LandMapper, NEP, and Self-Potential methods for Forensic and Archaeological Applications

detect burial places under uniform grass

Four-electrode probe for detection of burial places of criminal origin

We used electrical geophysical methods to measure the disturbance of the soil together with the properties of a hidden object itself. The study was conducted in collaboration with Russian Ministry of Internal Affairs to test methods for fast outlining soil disturbance places to help criminological search. The method is based on measurements of soil bulk electrical resistivity and principles of soil formation.

 

complex geophysical investigations in Kiev, Ukraine

Electrical geophysical methods to study subsurface water movement in urban areas

Hazardous hydrological situation caused by unknown factors appeared in Kiev-Pechersk Lavra (Kiev, Ukraine) near The Church of Holy Cross Elevation in 1987. The problem was attributable to temporary subsurface water fluxes fed by precipitation. Methods of 4-electrode profiling, vertical electrical sounding, and self-potential were utilized.

   

Locations

Westampton, NJ 40° 1' 14.1528" N, 74° 47' 31.992" W
Zelinograd, MOS 55° 59' 24.2736" N, 37° 9' 43.47" E
Kiev 50° 27' 0.36" N, 30° 31' 24.24" E

Electrical Geophysical Methods in Agriculture

Agriculture: a budding field in geophysicsMapping alluvial soils of humid areas with electrical geophysical methods: We tested the electrical geophysical methods of non-contact electrical profiling (NEP) and electrical profiling (EP) for mapping peat and mineral alluvial soils formed in the glacial valley of Yachroma river. More >>

Vertical Electrical Sounding to detect groundwater levels in arid areas: The approximate location of the groundwater table was estimated by a visual inspection of the VES curve. The AB/2 value with the sharp change to the low resistivity (3-20 ohm m) was selected from each VES profile...More >>

Evaluation of stone contents in soils with electrical geophysical methods to aid orchard planning: Geophysical methods of electrical resistivity, such as VES and four-electrode profiling provided the information about spatial distributions of stones in skeletal soils.  High resistivity will indicate the presence of stones in soil profiles. More >>

Application of the geophysical methods of electrical resistivity in precision farming:  One of the challenges facing the adoption of precision agriculture technology is the identification of productivity-related variability of soil properties accurately and cost-effectively. More >>

How-to use LandMapper and consumer-grade GPS data-logger to quickly map salinity on farm fields

GPS waypoints in Google EarthTask on hand: estimate salinity level on fields planned for rice next year. Six fields with total area of 322 acres were selected by farmer.

Equipment on hand: two LandMappers with different size probes attached (measuring electrical conductivity (EC) down to ~ 8” and 18”), Columbus GPS data-logger, all-road vehicle or “Mule”. Three people: farmer driving a '”mule” and recording data on paper, one person measuring with Landmapper at 18” depth, other person measuring EC with LandMapper to 8” depth and recording POI or way points with GPS. Results: 30 points recorded in less than 1.5 hour (including about 45 min break to wait out the rain). EC in the field varied from 5 mS/m to 106 mS/m on surface; and from 19 mS/m to 400 mS/m in deeper layer.

Местоположение

Farm Winnie, TX 29° 36' 14.6448" N, 94° 21' 7.0524" W
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