Turkish Journal of Earth Sciences
Abstract
The Bolu region, situated along the western–central segment of the North Anatolian Fault Zone (NAFZ), is characterized by a complex fault architecture in which multiple overlapping strike-slip segments and associated subsurface structures accommodate active crustal deformation. Although the principal fault strands of the NAFZ have been well mapped, several clusters of seismicity are observed in areas without clear surface fault expression, indicating the presence of subsurface or poorly expressed fault zones. In this study, we integrated edge detection methods with a seismicity approach to delineate active and buried structural features across the Bolu region. Bouguer gravity anomalies derived from the WGM2012 model were analyzed using four gradient-based filters: the total horizontal derivative, tilt derivative, tilt angle of the horizontal gradient, and modified horizontal gradient amplitude filters. Among these, the MHGA technique produced the most coherent and noise-resistant results, allowing sharper identification of lateral density contrasts associated with fault-related discontinuities. Integration of MHGA results with seismic data revealed several previously unmapped, seismically active subsurface lineaments (numbered as 1–49), indicating a distributed deformation pattern extending beyond the main NAFZ strand. These findings provide new geophysical evidence for potential faults in the Bolu region and underscore the utility of potential field methods for refining active fault maps and improving seismic hazard assessments in northwestern Anatolia.
DOI
10.55730/1300-0985.2024
Keywords
North Anatolian Fault Zone, Bolu region, gravity anomalies, modified horizontal gradient amplitude, edge detection, subsurface faults
First Page
354
Last Page
376
Publisher
The Scientific and Technological Research Council of Türkiye (TÜBİTAK)
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
DENİZ TOKTAY, H, & TAMTAŞ, B. D (2026). Integrated edge detection of gravity data and seismicity approach for mapping potential faults in the Bolu region. Turkish Journal of Earth Sciences 35 (4): 354-376. https://doi.org/10.55730/1300-0985.2024
