Delineation of the Cibojong Fault based on Morphotectonic analysis and UAV imagery in the Pamulihan area, Southern Garut, Indonesia

¹ Postgraduate Program of Geological Engineering, Universitas Padjadjaran, Bandung, Indonesia
² Geological Study Program, Institut Teknologi Nasional Yogyakarta, Indonesia
³ Faculty of Geological Engineering, Universitas Padjadjaran, Sumedang, Indonesia
⁴ British Geological Survey (BGS), Keyworth, United Kingdom
⁵ Geological Agency, Ministry of Energy and Mineral Resources, Bandung, Indonesia

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The Cibojong Fault in Pamulihan, Southern Garut, is an active tectonic structure whose existence has not been well defined due to dense vegetation cover and rapid weathering processes. This study aims to delineate the fault using a combination of morphotectonic analysis, UAV-based photogrammetry, and fracture orientation measurements. UAV imagery acquired at the Ciarinem and Cisompang rivers provided highresolution topographic models that highlight geomorphic anomalies such as offset valleys, escarpments, and drainage deflections. Field observations and joint orientation analysis confirmed dominant NW-SE fracture trends consistent with a strike-slip stress regime, supported by fracture density measurements indicating localized deformation zones. These findings demonstrate that the Cibojong Fault cuts across stratigraphic units ranging from the Pliocene to the Holocene, indicating persistent tectonic activity into recent geological times. The integrated approach of morphotectonic indices, UAV mapping, and structural field data provides a more accurate delineation of the Cibojong Fault and contributes to understanding its role in risk mitigation strategies and hazard assessment.