Dimensionality and Geoelectric Strike Analysis of 2D Magnetotelluric Modeling in Geothermal Area “XYZ”

• Published in: IOP conference series. Earth and environmental science 2024-07, Vol.1373 (1), p.12022
• Main Authors: Lestari, S F, Lestari, W, Fajar, M H M, Zarkasyi, A, Siagian, R R
• Format: Article
• Language: English
• Subjects: Distortion; Error analysis; Fractures; Geoelectricity; Geology; Geothermal resources; Lithology; Rotation; Tensor analysis; Tensors; Two dimensional analysis
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/1373/1/012022

Magnetotelluric (MT) method is crucial in geothermal exploration due to its capability to delineate geothermal prospect area by mapping subsurface resistivity distribution. However, in 2D Magnetotelluric modelling, galvanic distortion can distort the regional MT responses, leading to interpretation errors. This study employs phase tensor analysis to eliminate galvanic distortion. Results reveal the dimensionality of each station and three variations of the tipper strike, often referred to as the geoelectric strike. The tipper strike of each station showed varying values, while the tipper strike of all stations indicated N35°E. The tipper strike results required validation against additional geological information, such as faults, fractures, and changes in lithology, significantly influence the conductivity structure of subsurface, which indicated a geological strike of approximately N30°E. This study compares the MT data without rotation, rotation to tipper strike of each station, and tipper strike of all stations to assess effectiveness in eliminating galvanic distortion and improving data quality. The resulting 2D Magnetotelluric cross-section rotated to the tipper strike of all station, exhibits the lowest RMS Error of 2% and roughness of 654.6 among other variations, indicating improve quality. This interpretation identifies a geothermal system in the study area, closely aligning with actual subsurface geological conditions.