Research subject. The hill morphology formed in the study area, which is part of the Semilir Formation, is suspected to be a product of Opak fault reactivation. Further investigation is needed to substantiate this claim.Aim. To investigate the characteristics of the Opak Fault in the Semilir Formation. The study area is a red zone, which is an area damaged by the 2006 Opak Fault earthquake.Materials and Methods. This study was interpreted through integrated data that combined the Digital Elevation Model (DEM) from DEMNAS (Indonesian National Digital Elevation Model), the Digital Outcrop Model (DOM), and extensive field observations. The methodology employed involves investigating DOM interpretation combined with field surveys and morphotectonic methods.Results. We have identified the study area as divided into two segments: the northern and southern segments. The characterization of these segments is based on the differences in the alignment of landforms associated with the general direction of the hills and analysis from rosette diagrams. In the northern region, elongated hills are oriented in the NE-SW direction, whereas in the south, they exhibit an N-S block lineation. Field observations reveal the presence of a high-angle fault at observation point A (Fig. 6a), indicating reactivation, and a reverse fault at observation point D1 (Fig. 6b). The rosette diagram results indicate a compression direction of NW-SE in the northern segment and N-S in the southern segment.Conclusions. Integrating UAV photogrammetry and Digital Elevation Model (DEM) data has significantly enhanced our understanding of the geological structures within the Semilir Formation in the Opak Fault Zone. The analysis identifies the study area as a reactivation zone of the Opak fault, indicated by the presence of high-angle reverse faults. This reactivation zone and the landscape morphology consisting of hills are interpreted as a zone of destruction resulting from Opak fault movement, previously identified as a sinistral strike-slip fault.