Integrated GPR and electrical resistivity imaging for shallow fault detection in a tectonically active region: A case study in Bali, Indonesia

Khrisma Nawangsih; Korhan Cengiz

doi:10.58524/cesl/v1i1.121

Authors

Khrisma Nawangsih Department of Physics, Institut Teknologi Sumatera Author
Korhan Cengiz College of Information Technology University of Fujairah Author https://orcid.org/0000-0001-6594-8861

DOI:

https://doi.org/10.58524/cesl/v1i1.121

Keywords:

Ground penetrating radar, Electrical resistivity imaging, Shallow fault detection, Integrated geophysical methods, Seismic hazard assessment

Abstract

Bali Island is located within a tectonically active region influenced by the convergence of the Indo-Australian and Eurasian plates, making it highly susceptible to seismic hazards. One area with potential fault activity is Bangli Regency. This study aims to identify subsurface fault structures using an integrated geophysical approach combining Ground Penetrating Radar (GPR) and dipole–dipole electrical resistivity methods. Data were acquired along four survey lines in Lembean, Tembuku, Belantih, and Sukawana villages. Secondary geological data from the Geological Survey Center were also incorporated. The resistivity data were processed using RES2DINV, while GPR data were analyzed using ReflexW 7.1. The results reveal indications of fault-related anomalies in Belantih, Lembean, and Sukawana. In Belantih, GPR detected anomalies at a distance of 301 m with depths ranging from 1–6 m, while resistivity results indicated anomalies at 51 m with a depth of 20.2 m. In Lembean, anomalies were identified at 290 m with depths of 1–5 m from GPR data and at 144 m with a depth of 11.8 m from resistivity analysis. In Sukawana, GPR results showed a potential fault structure at 590 m with depths up to 8 m; however, this could not be validated by resistivity data due to acquisition errors. No significant fault-related anomalies were detected in Tembuku. These findings demonstrate the effectiveness of integrating GPR and electrical resistivity methods for shallow subsurface fault identification and provide important insights into local seismic risk assessment in Bangli Regency.

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