North-South and Vertical Deformation Across the Western Anatolian
Extensional Province (Türkiye) from Sentinel-1 InSAR
Abstract
Quantifying interseismic deformation of fault networks which are
predominantly deforming in a north-south direction is challenging,
because GNSS networks are usually not dense enough to resolve
deformation at the level of individual faults. The alternative,
synthetic aperture radar interferometry (InSAR), provides high spatial
resolution but is limited by a low sensitivity to N-S motion. We study
the active normal fault network of Western Anatolia, which is undergoing
rapid N-S extension, using InSAR. In the first part of this study, we
develop a workflow to assess the potential of decomposing InSAR
line-of-sight (LOS) velocities to determine the N-S component. We use
synthetic tests to quantify the impact of noise and other velocity
components and outline the requirements to detect N-S deformation in
future studies. In its current state, the N-S deformation field is too
noisy to allow robust interpretations, hence in the second part we
complement the study by including vertical deformation. Since most
faults in the study region are normal faults, the high-resolution
vertical velocity field provides new insights into regional active
faulting. We show that tectonic deformation in the large graben systems
is not restricted to the main faults, and seemingly less active or
inactive faults could be accommodating strain. We also observe a
potential correlation between recent seismicity and active surface
deformation. Furthermore, we find that active fault splays causing
significant surface deformation can form several kilometres away from
the mapped fault trace, and provide an estimate of current activity for
many faults in the region.