Euler deconvolution of a localized secondary fault of toru segment: the Batu Jomba landslide-prone road corridor

Landslide mitigation in active tectonic regions is a critical component of geo-environmental risk management, particularly in areas with steep topography near active fault zones. This study applies the Euler deconvolution formula on gravity data to delineate the presence of a localized secondary fault associated with the Toru Segment (a part of the Sumatran Fault Zone), within the landslide-prone road corridor in Batu Jomba. Previous studies in this area have primarily focused on fault slip rates and shallow-depth fault mapping, therefore, the detection of secondary fault activity intersecting the Toru Segment has not been explored. To address this gap, high-resolution gravity anomaly data from the GGMplus model (~۲۰۰ m resolution) were processed using geophysical inversion to image subsurface density variations and Euler deconvolution formula was applied to estimate the depth of these two areas. The Batu Jomba area is characterized by a low Bouguer density of ۲.۰۴۵۴ g/cm³, consistent with the Sihapas Formation dominated by weak sandstone lithology. Field observations corroborate the presence of sandstone boulders within the landslide body, indicating low material strength. Euler deconvolution results reveal the absence of direct structural expression beneath the Batu Jomba. However, clustered depth solutions in areas surrounding Batu Jomba delineate the presence of localized secondary fault at depths of ۱۹۳-۵۳۰ m, nearby the main Toru Segment. Regional Euler depth patterns indicate tectonic activity at depths of ۱۹۳-۵۹۰ m in part of the Toru Segment and ۱۹۳-۱,۰۸۲ m in the Angkola Segment. The shallower depth extent of the Toru Segment and Batu Jomba area when compared to the Angkola Segment supports the interpretation of localized crustal thinning in the Toru Segment region at shallow depths. These findings indicate that the Batu Jomba landslide-prone road corridor is controlled primarily by weak lithology and the nearby presence of secondary fault rather than the main Toru Segment. The results highlight the effectiveness of gravimetric methods, particularly Euler deconvolution in characterizing fault activity and geo-hazard assessment, offering practical implications for engineering planning and disaster-risk reduction.

کلیدواژه ها:

Batu Jomba ، Euler deconvolution ، Secondary fault ، Toru segment.