Tectonic structures of Lake Eğirdir (SW Türkiye) revealed by magnetic analysis

Lake Eğirdir, located within the tectonically complex Isparta Angle of southwestern Türkiye, hosts an actively deforming transtensional basin shaped by multidirectional stresses. Although the surrounding fault systems have been studied previously, the subsurface fault architecture beneath the lake remained largely unresolved. Understanding the lake's subsurface tectonic framework is crucial for regional geological and seismic assessments. This study addresses this gap by applying traditional and advanced edge detection techniques to identify magnetic lineaments and assess their connection with surrounding faults using newly acquired high-resolution magnetic data, corrected for noise and distortions. The distinct magnetic lineaments identified confirm a structural connection on land with the regional fault network around the lake, also showing their continuity under the lake. The results reveal dominant NW-SE and E-W trending magnetic lineaments. The most prominent structure identified within the lake is a NE-SW fault that cuts the NW-SE anomalies and is spatially related to the Yaka Fault on land. Its continuation beneath the lake is confirmed by clustered seismicity and normal fault-type focal mechanisms, indicating active transtensional deformation. These findings highlight active faulting processes that continue to shape the lake basin and contribute to understanding regional seismic hazards. Integration of magnetic, bathymetric, seismic, and geodetic datasets reveals that Lake Eğirdir acts as a dynamic neotectonic transfer zone within the Isparta Angle, facilitating the westward extrusion of the Anatolian Plate.