A review of open software resources in python for electrical resistivity modelling

Geophysical modelling performs to obtain subsurface structures in agreement with measured data. Freeware algorithms for geoelectrical data inversion have not been widely used in geophysical communities; however, different open-source modelling/inversion algorithms were developed in recent years. In this study, we review the structures and applications of openly Python-based inversion packages, such as pyGIMLi (Python Library for Inversion and Modelling in Geophysics), BERT (Boundless Electrical Resistivity Tomography), ResIPy (Resistivity and Induced Polarization with Python), pyres (Python wrapper for electrical resistivity modelling), and SimPEG (Simulation and Parameter Estimation in Geophysics). In addition, we examine the recovering ability of pyGIMLi, BERT, ResIPy, and SimPEG freeware through inversion of the same synthetic model forward responses. A versatile pyGIMLi freeware is highly suitable for various geophysical data inversion. The SimPEG framework is developed to allow the user to explore, experiment with, and iterate over multiple approaches to the inverse problem. In contrast, BERT, pyres, and ResIPy are exclusively designed for geoelectric data inversion. BERT and pyGIMLi codes can be easily modified for the intended applications. Both pyres and ResIPy use the same mesh designs and inversion algorithms, but pyres uses scripting language, while ResIPy uses a graphical user interface (GUI) that removes the need for text inputs. Our numerical modelling shows that all the tested inversion freeware could be effective for relatively larger targets. pyGIMLi and BERT could also obtain reasonable model resolutions and anomaly accuracies for small-sized subsurface structures. Based on the heterogeneous layered model and experimental target scenario results, the geoelectrical data inversion could be more effective in pyGIMLi, BERT, and SimPEG freeware packages. Moreover, this study can provide insight into implementing suitable inversion freeware for reproducible geophysical research, mainly for geoelectrical modelling.

WENNER'S CONFIGURATION GEOELECTRIC METHOD FOR THE INTERPRETATION OF THE SUBSURFACE STRUCTURES OF PANUNGKIRAN VILLAGE

<p><em>A research has been carried out which aims to determine the subsurface structure using the geoelectric method in Panungkiran Village, Kab. Deli Serdang, Prov. North Sumatra Geoelectric data retrieval uses the Wenner configuration to determine the distribution and depth of subsurface structures in Panungkiran Village, Deli Serdang Regency. Prov. North Sumatra Data collection is 1 track with a length of 90 meters, Data processing in the study using MS office software Excel Notepad, and RES2DINV The results of the measurements consist of several types which are distinguished based on the range of resistivity values, namely in the range of 34.0-3188 2m interpreted by lithological layers topsoil (34.0-65.1</em> Ωm<em>), sandstone (65.1-1252</em> Ωm<em>) weathered tr</em><em>a</em><em>vertine limestone (125-456</em> Ωm<em>), fresh trvertine limestone (456-3188</em> Ωm<em>), and resistivity &gt;3188 Qm is interpreted as a cave at a depth of 9-12 meters.</em><em></em></p>

Pendugaan sebaran intrusi air laut melalui sungai di desa Ujungmanik kecamatan Kawunganten kabupaten Cilacap menggunakan metode geolistrik resistivitas konfigurasi Wenner

The estimation of the distribution of the sea water intrusion through the rivers in Ujungmanik Village, Kawunganten District, Cilacap Regency has been carried out using the Wenner configuration resistivity geoelectric. This research aims to estimate the distribution of sea water intrusion through rivers in Ujungmanik Village, Kawunganten District, Cilacap Regency based on geoelectric resistivity and conductivity data of groundwater. The geoelectric data acquisition was carried out on four lines. They were Wen1 Line, Wen2 Line, Wen3 Line, and Wen4 Line. Each line had a range of 200 meters. The results of geoelectric data processing showed that the subsurface rock structure consisted of sand, clay, sandy loam, and sandy clay. The Seawater intrusion shown by the sand layer occurred in all trajectories which had a range of resistivity value of 0.20 - 2.79 Ωm. Groundwater samples was carried out at fifteen points with the conductivity value varies between 1363 - 4145 µS / cm so that they can be classified that the water was fresh and brackish due to the sampling done in the rainy season. From this research it can be implied that the entire Ujungmanik area is evenly intruded by the sea water at the coordinates 7º38ꞌ15.62ꞌꞌLS 108°57ꞌ20.89ꞌꞌBT to 7º39ꞌ22.86ꞌꞌLS 108º56ꞌ35.33ꞌꞌBT.

ANALYSIS OF CAUSES OF SUBSIDENCE IN THE AREA NEAR UJUNGNEGORO STATION, BATANG REGENCY

Changes in human activities from time to time increase rapidly. This activity requires the support of a reliable transportation network. Railroad land transportation is the main choice to overcome the impasse of human mobility and distribution of goods. It is known that this type of transportation does not intersect with other means of transportation so that it is free from congestion. For the sake of smoothness and safety in the use of trains, proper maintenance of the rail network is needed. Land subsidence supporting the railroad tracks is a common event that disrupts the functioning of the railroad and is part of maintenance. One of the subsidence that often occurs on the railroad tracks is a subsidence on the railroad tracks around Ujungnegoro Station. To find out the cause, an analysis of geoelectric data, groundwater basin conditions and local topography has been carried out on it. The results of the analysis that have been carried out conclude that the clay content factor and the concentration of water flow are the main factors causing subsidence.

Calculation of Limestone Reserves in the East Biluhu Region, Gorontalo district, Gorontalo Province

<em>Indonesia is a country that has a lot of natural resources. Natural resources are widely used in various areas of human life. One of the resources that is often used is limestone. Limestone is a non-metallic mining material that has considerable potential and reserves and spreads across almost all parts of Indonesia, but the exact amount of reserves is not yet known. The research aims to predict the amount of packstone-type limestone reserves using geophysical methods. This research was conducted using the geoelectric method with the Schlumberger configuration, where the resistivity geoelectric data obtained variations in resistivity and layer thickness. From this data, it is then interpreted to determine the type of rock in the surface area, and making a 3D model to determine the distribution of limestone in the study area and to calculate the amount of limestone reserves in the study area. Based on the research results, it is known that the research area is dominated by packstone with a resistivity value of 16.6 Ωm - 1.3x105 Ωm. The calculation result of packstone reserves in the study area is </em>73,629,403<em>tons.</em>

PENENTUAN DIAMETER PIPA OPTIMAL DALAM PERENCANAAN SISTEM PENYEDIAAN AIR BERSIH DI KECAMATAN WONOTIRTO KABUPATEN BLITAR PROVINSI JAWA TIMUR

Optimization of pipe diameter in the planning of clean water supply systems in Wonotirto District aims to determine the projected demand for clean water in Wonotirto District until 2028. This research was conducted because currently the distribution of clean water in the study location is still not completely fulfilled. Topographical conditions, most of which are in mountainous areas, cause one of the reasons for the difficulty of distributing clean water. The pipe diameter optimization planning in this study uses the Hazen-William method. The data used are the population in the last 10 years, geoelectric data, and topographic maps of Wonotirto District, Blitar Regency. Based on the results of the planning, it is found that the projected number of population in 2020 is 37,013 people. the discharge of clean water needs is 63.73 liters / second, the dimensions of reservoir 1 are planned to be 6 m x 4 m x 3 m, reservoir 2 is planned to be 6.5 m x 4 m x 3 m. The type of pipe used is the type of PVC with a diameter of 0.75 inches, 1 inch, 1.25 inches, 1.5 inches, 2 inches, 2.5 inches, 3 inches, 4 inches, 6 inches, where planning calculations are carried out using the Hazen-William Method. The limited amount of groundwater discharge at the location means that not all villages in the Wonotirto District area have their clean water needs met and it is hoped that further research will improve this research.

The deep structure of mineragenetic zones in Southern Primorye

The deep structure of mineragenetic zones under the Spassk-Dalniy-Zerkalnaya Bay geotraverse has been derived from the integrated interpretation of seismic, density, magnetic, and geoelectric data. The studies demonstrate that geophysical methods based on different physical principles reflect various characteristics of lithosphere elements. Large sets of the obtained geophysical data provide crucial information on structural features and physical characteristics of mineragenetic objects to understand the genesis of endogenous mineralization of various types and develop new approaches to forecasting.

Application of geological and electrical resistivity methods for groundwater studies at Tatiko, North Central Nigeria

The success probability of water wells constructed in crystalline rock terrains is largely dependent on the size, location and interconnectivity of the fractures present in them as well as the amount and nature of the material that may clog the fractures. Geological and geoelectrical studies were proposed and conducted at Tatiko to determine the structures in the underlying basement rocks and evaluate their groundwater potential. Geological study was used to delineate the structural control on groundwater availability while the geoelectrical study (Vertical Electrical Sounding) was used to investigate the properties of the subsurface materials and determine their potential to host sufficient quantity of groundwater.Structural data were plotted on a rosset diagram and showed major structural control trending in the NW – SE direction. Quantitative interpretation of the geoelectric data indicates that the major fractures are within the weathered to competent basement indicating good hydraulic connection between the weathered and fresh basement. The fractures are deepest within the region that showed thicker weathering and are as shallow as 7 meters in other regions. Apparent resistivity of the fractures ranges between 100Ωm and 1200Ωm in most parts of the area with the highest values in the west. An integration of the result clearly showed that the NW and SW parts of the study area are the most favourable for drilling and further groundwater studies and drilling is recommended to a depth of 40m to 50m. Keywords: Groundwater, Geoelectrical study, Fractures, Tatiko, Resistivity, Basement Complex.