Original scientific paper
https://doi.org/10.17794/rgn.2026.4.6
MODELLING THE EFFECTS OF LATERAL LOADING ON A BENT STRIKE-SLIP FAULT SYSTEM: A CASE STUDY FROM THE PALU-KORO AND MATANO FAULTS, INDONESIA
Dian Kusumawati
; Geophysical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia.;Research Center for Geological Disaster, National Research and Innovation Agency (BRIN), Bandung 40135, Indonesia.
David P. Sahara
; Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia.
Nanang T. Puspito
; Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia.
*
Mudrik R. Daryono
; Earthquake Research Group, National Research and Innovation Agency (BRIN), Bandung 40135, Indonesia.
Andri D. Nugraha
; Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia.
Andrean V. H. Simanjuntak
; Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG), Jakarta 10720, Indonesia.; Department of Geophysical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia.
Maulidia Ain Bening
; Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia.
Faiz Muttaqy
; Research Center for Geological Disaster, National Research and Innovation Agency (BRIN), Bandung 40135, Indonesia.
* Corresponding author.
Abstract
The Palu–koro and Matano faults form a major bent strike-slip fault system in central Sulawesi, Indonesia, accommodating significant crustal deformation associated with regional plate interactions. In this study, we investigate the mechanical response of this fault system using three-dimensional numerical modelling to evaluate how different lateral loading configurations influence fault slip and stress patterns. Dirichlet (displacement-rate) boundary conditions, inferred from regional plate velocities, are applied to the model domain at the x-face, y-face, and in combined x- and y-face configurations. Models with pure x-face or y-face loading generate lateral slip patterns that are mechanically compatible with idealized Riedel shear kinematics; however, the resulting slip sense differs from the present day tectonic motion of the Palu–koro and Matano faults. In contrast, models with combined boundary conditions reproduce first-order characteristics of the observed fault behaviour. In particular, scenarios with dominant lateral loading at the x-face (e.g. 70% x-face and 30% y-face) produce predominantly sinistral slip along both faults and higher slip concentrations along the Palu–
koro Fault, consistent with tectonic and geodetic observations. The combined loading models also exhibit a subtle rotation of the maximum principal stress orientation from WNW–ESE along the Palu–koro Fault to NE–SW along the Matano Fault, which is qualitatively consistent with stress orientations inferred from focal mechanism inversions. Overall, the results suggest that combined regional lateral loading, with a dominant north–south lateral movement, provides a plausible mechanical framework for understanding deformation localization and stress rotation within the Palu–koro–Matano fault system.
Keywords
bent strike-slip; fault lateral slip; fault tensile slip; Matano Fault; numerical modelling; Palu-koro Fault; Riedel shear
Hrčak ID:
349887
URI
Publication date:
21.7.2026.
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