Late Quaternary deformation in the western extension of the North Anatolian Fault (North Evia, Greece): Insights from very high-resolution seismic data (WATER surveys)

Abstract

Since the Pliocene, rift basins have developed in the North Evia region at the south-western extension of the North Anatolian Fault. North Evia, therefore, is a key area for investigating Plio-Quaternary deformation within the diffuse Anatolian-Aegean–Eurasian plate boundary. In this study, we present a detailed map of offshore faults in the North Evia region based on three seismic reflection surveys: an airgun (2004) and two very high-resolution Sparker (2017 and 2021) single-channel surveys. Careful and systematic interpretation of these datasets revealed i) the identification of a new basin (Skiathos Basin) located at the western extension of the North Anatolian Fault and ii) two main fault sets striking oblique to the active N–S-directed extension. The seismicity analysis of the study area reveals pure strike-slip displacements along faults previously identified as normal. The NW–SE-striking faults bordering the North Evia Gulf rift are characterised by left-lateral displacements, and the NE–SW faults present dextral focal mechanisms, following the kinematic character of the North Anatolian Fault. We show that dextral strike-slip deformation recently occurred (in the late Quaternary) in the south-western extension of the North Anatolian Fault, suggesting the significant role of this fault system in the complex structural development of the North Evia region.