Resolving near-surface fault architecture in a complex volcanic–sedimentary setting using integrated geophysical methods
DOI:
https://doi.org/10.58524/cesl/v1i1.126Keywords:
Ground penetrating radar, Near-surface faulting, Electrical resistivity imaging, Volcanic–sedimentary environment, Integrated geophysical methodsAbstract
Badung Regency (Bali, Indonesia) is a seismically active region where earthquake events may reactivate local fault systems, posing significant geohazard risks. However, the subsurface fault architecture in this area remains poorly constrained. This study aims to delineate subsurface structures and identify fault zones by integrating Ground Penetrating Radar (GPR) and 2D electrical resistivity imaging using a dipole–dipole configuration. Secondary datasets, including radargrams and geoelectrical measurements, were reprocessed and interpreted using ReflexW 7.0, RES2DINV, and AGI EarthImager. The combined analysis reveals a heterogeneous subsurface composed of clay-rich units (mudstone and silt), alluvium, tuff, breccia, gravel, sand, and limestone. Inverted resistivity values range from 3 to 5116 Ω·m, corresponding to depths of approximately 0.5–50.7 m. Fault zones are inferred from (i) low-resistivity clay layers acting as potential weak zones and (ii) discontinuities and non-hyperbolic reflections observed in GPR profiles. GPR data indicate shallow fault-related features at distances of 280–1100 m along survey lines and depths of 1–8 m. In contrast, resistivity imaging identifies deeper structural discontinuities at distances of 47–196 m and depths of 0.6–39.3 m. The discrepancy in detected depths highlights the complementary sensitivity of both methods to different structural scales. These results demonstrate that integrating GPR and electrical resistivity imaging provides a robust approach for resolving near-surface fault geometry in complex volcanic–sedimentary environments. The identified fault zones may represent reactivated structures associated with regional seismicity, underscoring their importance for local hazard assessment and land-use planning.
References
1. Hosono, T., Hartmann, J., Louvat, P., Amann, T., Washington, K. E., West, A. J., Okamura, K., Böttcher, M. E., & Gaillardet, J. (2018). Earthquake-induced structural deformations enhance long-term solute fluxes from active volcanic systems. Scientific Reports, 8(1), 1–12. https://doi.org/10.1038/s41598-018-32735-1
2. Zhang, Z., Yao, H., Wang, W., & Liu, C. (2021). 3-D crustal azimuthal anisotropy reveals multi-stage deformation processes of the Sichuan Basin and its adjacent regions. Journal of Geophysical Research: Solid Earth, 127, e2021JB023289, 1–17. https://doi.org/10.1029/2021JB023289
3. Liu, S., Suardi, I., Xu, X., Yang, S., & Tong, P. (2021). The geometry of the subducted slab beneath Sumatra revealed by regional and teleseismic traveltime tomography. Journal of Geophysical Research: Solid Earth, 126(1), 1–29. https://doi.org/10.1029/2020JB020169
4. Dewi, K. C. S., Siregar, R. N., Ningati, T. I., Pulungan, Z. N., Indriyawati, A., & Takahashi, H. (2025). Analysis of subsurface faults using 3D gravity method based on satellite image data: Insights into Indo-Australian and Eurasian plate subduction in the formation of an accretionary prism. International Journal of Hydrological and Environmental for Sustainability, 4(3), 135–148. https://doi.org/10.58524/ijhes.v4i3.960
5. Hariyono, E., & S, L. (2018). The characteristics of volcanic eruption in Indonesia. In Volcanoes – Geological and Geophysical Setting, Theoretical Aspects and Numerical Modeling, Applications to Industry and Their Impact on Human Health. https://doi.org/10.5772/intechopen.71449
6. McCaffrey, R. (2009). The tectonic framework of the Sumatran subduction zone. Annual Review of Earth and Planetary Sciences, 37, 345–366. https://doi.org/10.1146/annurev.earth.031208.100212
7. Hristov, V., Stoyanov, N., Valtchev, S., Kolev, S., & Benderev, A. (2019). Utilization of low enthalpy geothermal energy in Bulgaria. IOP Conference Series: Earth and Environmental Science, 249(1). https://doi.org/10.1088/1755-1315/249/1/012035
8. Taruna, R. M., & Banyunegoro, V. H. (2018). Earthquake relocation using double difference method for 2D modelling of subducting slab and back arc thrust in West Nusa Tenggara. Jurnal Penelitian Fisika dan Aplikasinya (JPFA), 8(2), 132–143. https://doi.org/10.26740/jpfa.v8n2.p132-143
9. Collings, R., Lange, D., Rietbrock, A., Tilmann, F., Natawidjaja, D., Suwargadi, B., Miller, M., & Saul, J. (2012). Structure and seismogenic properties of the Mentawai segment of the Sumatra subduction zone revealed by local earthquake traveltime tomography. Journal of Geophysical Research, 117, 1–23. https://doi.org/10.1029/2011JB008469
10. Jihad, A., Muksin, U., Syamsidik, & Ramli, M. (2021). Earthquake relocation to understand the megathrust segments along the Sumatran subduction zone. IOP Conference Series: Earth and Environmental Science, 630, 012002. https://doi.org/10.1088/1755-1315/630/1/012002
11. Xu, J., & Kono, Y. (2002). Geometry of slab, intraslab stress field and its tectonic implication in the Nankai Trough, Japan. Earth, Planets and Space, 54(7), 733–742. https://doi.org/10.1186/BF03351726
12. Kusuhara, F., Kazahaya, K., Morikawa, N., Yasuhara, M., Tanaka, H., Takahashi, M., & Tosaki, Y. (2020). Original composition and formation process of slab-derived deep brine from Kashio Mineral Spring in central Japan. Earth, Planets and Space, 72(1). https://doi.org/10.1186/s40623-020-01225-y
13. Malod, J. A., Karta, K., Beslier, M. O., & Zen, M. T. (1995). From normal to oblique subduction: Tectonic relationships between Java and Sumatra. Journal of Southeast Asian Earth Sciences, 12(1–2), 85–93. https://doi.org/10.1016/0743-9547(95)00023-2
14. Li, C. F. (2011). An integrated geodynamic model of the Nankai subduction zone and neighboring regions from geophysical inversion and modeling. Journal of Geodynamics, 51(1), 64–80. https://doi.org/10.1016/j.jog.2010.08.003
15. Stern, R. J. (2002). Subduction zones. Reviews of Geophysics, 40(4), 3-1–3-38. https://doi.org/10.1029/2001RG000108
16. Utama, H. W., Mulyasari, R., & Said, Y. M. (2021). Geothermal potential on Sumatra Fault System for sustainable geotourism in West Sumatra. JGE (Jurnal Geofisika Eksplorasi), 7(2), 126–137. https://doi.org/10.23960/jge.v7i2.128
17. Tabei, T., Hashimoto, M., Miyazaki, S., Hirahara, K., Kimata, F., Matsushima, T., Tanaka, T., Eguchi, Y., Takaya, T., Hoso, Y., Ohya, F., & Kato, T. (2002). Subsurface structure and faulting of the Median Tectonic Line, southwest Japan inferred from GPS velocity field. Earth, Planets and Space, 54(11), 1065–1070. https://doi.org/10.1186/BF03353303
18. Tongkul, F. (2017). Active tectonics in Sabah – seismicity and active faults. Bulletin of the Geological Society of Malaysia, 64, 27–36. https://doi.org/10.7186/bgsm64201703
19. Maryanto, S. (2017). Geo techno park potential at Arjuno–Welirang volcano hosted geothermal area, East Java, Indonesia (multi geophysical approach). AIP Conference Proceedings, 1908. https://doi.org/10.1063/1.5012712
20. Sujitapan, C., Kendall, J. M., Chambers, J. E., & Yordkayhun, S. (2024). Landslide assessment through integrated geoelectrical and seismic methods: A case study in Thungsong site, southern Thailand. Heliyon, 10(2), e24660. https://doi.org/10.1016/j.heliyon.2024.e24660
21. Chambers, J., Holmes, J., Whiteley, J., Boyd, J., Meldrum, P., Wilkinson, P., Kuras, O., Swift, R., Harrison, H., Glendinning, S., Stirling, R., Huntley, D., Slater, N., & Donohue, S. (2022). Long-term geoelectrical monitoring of landslides in natural and engineered slopes. The Leading Edge, 41(11), 768–776. https://doi.org/10.1190/tle41110768.1
22. Whiteley, J. S., Watlet, A., Uhlemann, S., Wilkinson, P., Boyd, J. P., Jordan, C., Kendall, J. M., & Chambers, J. E. (2021). Rapid characterisation of landslide heterogeneity using unsupervised classification of electrical resistivity and seismic refraction surveys. Engineering Geology, 290, 106189. https://doi.org/10.1016/j.enggeo.2021.106189
23. Martinho, E. (2023). Electrical resistivity and induced polarization methods for environmental investigations: An overview. Water, Air, & Soil Pollution, 234. https://doi.org/10.1007/s11270-023-06214-x
24. Kusumayudha, S. B., Lestari, P., & Paripurno, E. T. (2018). Eruption characteristic of the sleeping volcano Sinabung, North Sumatera, Indonesia, and SMS gateway for disaster early warning system. Indonesian Journal of Geography, 50(1), 70–77. https://doi.org/10.22146/ijg.17574
25. Meju, M. A., & Le, L. (2002). Geoelectromagnetic exploration for natural resources: Models, case studies and challenges. Surveys in Geophysics, 23, 133–205.
26. Lange, D., Tilmann, F., Henstock, T., Rietbrock, A., Natawidjaja, D., & Kopp, H. (2018). Structure of the central Sumatran subduction zone revealed by local earthquake travel-time tomography using an amphibious network. Solid Earth, 9(4), 1035–1049. https://doi.org/10.5194/se-9-1035-2018
27. Lin, J. Y., Sibuet, J. C., Hsu, S. K., & Wu, W. N. (2014). Could a Sumatra-like megathrust earthquake occur in the South Ryukyu subduction zone? Earth, Planets and Space, 66(1), 1–8. https://doi.org/10.1186/1880-5981-66-49
28. Siringoringo, L. P., Sapiie, B., Rudyawan, A., & Sucipta, I. G. B. E. (2024). Origin of high heat flow in the back-arc basins of Sumatra: An opportunity for geothermal energy development. Energy Geoscience, 5(3), 100289. https://doi.org/10.1016/j.engeos.2024.100289
29. Hochstein, M. P., & Sudarman, S. (1993). Geothermal resources of Sumatra. Geothermics, 22(3), 181–200. https://doi.org/10.1016/0375-6505(93)90042-L
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Muhammad Amri Aziz Hakim, Shreeniwas Omanwar (Author)
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
