scholarly journals Interpretasi Electrical Resistivity Tomography (ERT) untuk Pendugaan Air Tanah Dangkal pada Formasi Gunungapi Muda

2020 ◽  
Vol 3 (1) ◽  
pp. 49 ◽  
Author(s):  
Erik Febriarta ◽  
Suswanti Suswanti ◽  
Sembodo Noviandaru
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Soil Surface ◽  
Igneous Rocks ◽  
Shallow Aquifer ◽  
Rock Outcrops ◽  
Resistivity Tomography ◽  
Surface Appearance ◽  
Hydrogeological Characteristics ◽  
Groundwater Basin

Aquifers or groundwater saturated areas in the slope morphology of Merapi volcano are relatively thin due to massive rock outcrops above the surface. Because these massive igneous rocks dominate the local geological appearance, the groundwater potential on the upper foot slope is relatively lower than the lower one that has thicker aquifer materials (sand). This study was designed to investigate the thickness of potential groundwater and identify the aquifer materials by geoelectrical methods using the Electrical Resistivity Tomography (ERT) configuration. ERT has several advantages, including its ability to present multi-log lithology vertically and produce a more detailed surface appearance. In this study, rock resistivity values were measured with a survey line stretching across 250 m. The geoelectrical imaging produced actual values (potential values) of the rock resistivities through the matching curve and inversion techniques. Afterward, the actual resistivities were matched with the standard electrical resistivity of rocks and their respective hydrogeological characteristics, i.e., the capacity to store and transmit water. Interpretation on rock resistivities detected groundwater at a depth of 0.5-12 m in Manisrenggo. This shallow aquifer has an impermeable layer composed of igneous rocks, which are massive breccia, that lie in one layer of sand. According to the Groundwater Basin Map, these rock formations are part of the Karanganyar-Boyolali Groundwater Basin. The shallow aquifers and hydraulic gradient lead to the emergence of seeps or flushes on the soil surface.

IDENTIFICATION OF AQUIFER USING RESISTIVITY GEOELECTRIC METHOD IN REGIONAL OF BEBANDEM, KARANG ASEM, BALI

2018 ◽  
Vol 19 (1) ◽  
pp. 24-34
Author(s):  
Budy Santoso
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Geophysical Methods ◽  
Soil Surface ◽  
Water Source ◽  
Resistivity Tomography ◽  
Resistivity Method ◽  
Surface Image ◽  
Resistivity Variation ◽  
Resistivity Meter

Bungaya Kangin Village, Bebandem District, Karangasem Regency, Bali Province consists of paddy fields and settlements, required therefore a water source / aquifer  that can meet all these needs. One of the Geophysical Methods that can identify the aquifer is the Geoelectric Method. Geoelectric method used in this research is Resistivity Method. Data acquisition using Vertical Electrical Sounding (VES) and Electrical Resistivity Tomography (ERT) Methods. VES method is a method of measurement to determine the variation of resistivity vertically at one point. Electrical Resistivity Tomography (ERT) method is a method of measuring resistivity on soil surface / rock by using many electrode (51 electrode), to obtain sub-surface resistivity variation  lateraly and verticaly, to obtain sub-surface image. The equipment used for geoelectric measurements is  Resistivity Meter of Naniura NRD 300 Hf which has been equipped with a switchbox to adjust the displacement of 51 electrodes. Based on the resistivity modeling results, the aquifers in the study area were found in rough sandstones with resistivity values : (49 - 100) Ohm.m.  

scholarly journals A new approach for time-lapse data weighting in electrical resistivity tomography

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. E325-E333 ◽  
Author(s):  
Nolwenn Lesparre ◽  
Frederic Nguyen ◽  
Andreas Kemna ◽  
Tanguy Robert ◽  
Thomas Hermans ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Time Lapse ◽  
Shallow Aquifer ◽  
Data Sets ◽  
Resistivity Tomography ◽  
New Approach ◽  
Data Weighting ◽  
Data Error ◽  
Over Time

Applications of time-lapse inversion of electrical resistivity tomography allow monitoring variations in the subsurface that play a key role in a variety of contexts. The inversion of time-lapse data provides successive images of the subsurface properties showing the medium evolution. Image quality is highly dependent on the data weighting determined from the data error estimates. However, the quantification of errors in the inversion of time-lapse data has not yet been addressed. We have developed a methodology for the quantification of time-lapse data error based on the analysis of the discrepancy between normal and reciprocal readings acquired at different times. We applied the method to field monitoring data sets collected during the injection of heated water in a shallow aquifer. We tested different error models to indicate that the use of an appropriate time-lapse data error estimate yielded significant improvements in terms of imaging. An adapted inversion weighting for time-lapse data implies that the procedure does not allow an over-fitting of the data, so the presence of artifacts in the resulting images is greatly reduced. Our results determined that a proper estimate of time-lapse data error is mandatory for weighting optimally the inversion to obtain images that best reflect the evolution of medium properties over time.

scholarly journals IMAGING TREE ROOT ZONE GEOMETRY USING ELECTRICAL RESISTIVITY TOMOGRAPHY

2020 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
Asep Mulyono ◽  
Ilham Arisbaya ◽  
Yayat Sudrajat
Keyword(s):  
Electrical Resistivity ◽  
Cross Sections ◽  
Electrical Resistivity Tomography ◽  
Root Zone ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Soil Surface ◽  
Resistivity Tomography ◽  
Root Plate ◽  
Maesopsis Eminii

Root zone geometry research is usually done in a conventional way which is destructive, time-consuming, and requires a considerable cost. Several non-destructive measurements used geophysical methods have been developed, one of which is the Electrical Resistivity Tomography (ERT) method. Tree root zone determination using ERT has been carried out in Kiara Payung area, Sumedang, West Java, with Maesopsis eminii tree as the object study. A total of 29 ERT lines were measured using dipoledipole configuration with electrodes spacing of 50 cm. The results of two-dimensional (2D) and three-dimensional (3D) inversion modeling show that the ERT method has been successfully imaging the tree root zone. The root zone is characterized as 100-700 Ωm with an elliptical shape geometry of the root plate. The root radius is estimated to be 4-5 m from the stem, the root zone diameter reaches 8-9 m at the shallow soil surface and the root zone depth is approximately 2-2.5 m. ABSTRAK Pencitraan geometri zona perakaran pohon menggunakan electrical resistivity tomography. Penelitian geometri zona perakaran biasa dilakukan dengan cara konvensional yang destruktif, memakan waktu, dan membutuhkan biaya yang tidak sedikit. Beberapa pengukuran non-destruktif menggunakan metode geofisika telah dikembangkan, salah satunya adalah metode Electrical Resistivity Tomography (ERT). Penentuan zona perakaran pohon menggunakan metode ERT telah dilakukan di daerah Kiara Payung, Sumedang, Jawa Barat, dengan pohon Maesopsis eminii sebagai objek studi. Sebanyak 29 lintasan ERT diukur menggunakan konfigurasi dipole-dipole pada dengan jarak antar elektroda 50 cm. Hasil pemodelan inversi dua dimensi (2D) dan tiga dimensi (3D) menunjukkan bahwa metode ERT telah berhasil mencitrakan zona perakaran pohon. Zona perakaran teridentifikasi berada pada nilai resistivitas 100-700 Ωm dengan root plate dan root cross-sections berbentuk elips. Radius akar diperkirakan sejauh 4-5 m dari pangkal batang, sedangkan diameter zona perakaran mencapai sekitar 8-9 m di permukaan tanah dangkal dan kedalaman zona perakaran diperkirakan antara ~2-2.5 m. 

scholarly journals High-Resolution Electrical Resistivity Tomography (ERT) to Characterize the Spatial Extension of Freshwater Lenses in a Salinized Coastal Aquifer

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1067 ◽  
Author(s):  
Nicolas Greggio ◽  
Beatrice Giambastiani ◽  
Enrico Balugani ◽  
Chiara Amaini ◽  
Marco Antonellini
Keyword(s):  
Electrical Resistivity ◽  
High Resolution ◽  
Electrical Resistivity Tomography ◽  
Decision Makers ◽  
Shallow Aquifer ◽  
Electrode Spacing ◽  
Coastal Zones ◽  
Aquifer Recharge ◽  
Resistivity Tomography ◽  
Freshwater Lenses

High-resolution electrical resistivity tomography (ERT) with electrode spacing of 1 m proved to be an effective methodology to characterize ephemeral, sparse, and discontinuous freshwater lenses within the almost completely salinized shallow aquifer of the low coastal zone near Ravenna. ERT profiles with a vertical resolution of 0.25–0.5 m, once calibrated with groundwater data (water table depth and electrical conductivity) collected in multi-level sampler systems at the same spatial resolution, are reliable and provide repeatable measurements in time. The ERT methodology allows for fast data acquisition over large areas and it also permits the study of the evolution in time of freshwater availability in coastal zones, which is important for local ecosystems and soil resources. This makes high-resolution ERT a valid tool to aid local stakeholders and decision makers to effectively manage freshwater lenses, and guarantee their preservation or augmentation by means of managed aquifer recharge.

Imaging subsurface migration of dissolved CO2 in a shallow aquifer using 3-D time-lapse electrical resistivity tomography

2014 ◽  
Vol 101 ◽  
pp. 31-41 ◽  
Author(s):  
Esben Auken ◽  
Joseph Doetsch ◽  
Gianluca Fiandaca ◽  
Anders Vest Christiansen ◽  
Aurélie Gazoty ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Time Lapse ◽  
Shallow Aquifer ◽  
Resistivity Tomography
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