Spatiotemporal variation in surface deformation of the North Anatolian Fault Zone in the Düzce Region by Geodetic and Geophysical techniques

Abstract Türkiye has a complex tectonic structure resulting from the northward movement of the African and Arabian plates towards the Anatolian plate relative to the Eurasian plate. Seismic energy is primarily released within the Anatolian plate by earthquakes along the North Anatolian Fault Zone (NAFZ), which is oriented east-west with a right-lateral strike-slip motion. Historical earthquake records suggest a westward migration of seismic energy release along this fault system through a series of earthquakes, beginning with the 1939 M7.9 Erzincan earthquake and culminating in the 1999 M>7 Izmit-Düzce ruptures. The 1999 Mw7.2 Düzce earthquake occurred three months after the 1999 Mw7.4 Izmit earthquake to the east leading to an eastward supershear rupture. We examine the potential correlation between crustal features, fault mechanisms, and inter-seismic loading parameters that impact surface deformation in Düzce. We analyzed spatio-temporal variation of the long-term surface deformation along the Düzce segment. We evaluated Sentinel-1 InSAR data for both ascending and descending orbits from 2014 to 2022, utilizing the InSAR Small Baseline Subset time series analysis technique to calculate horizontal and vertical displacements and the locking depth. Our findings indicate 25 mm/yr of slip rate on the Düzce Fault. We further utilize the previously estimated geoelectric characteristics of the crust by magnetotelluric data modeling that show strong resistivity variations from east to west on the Düzce rupture. Incorporating geodetic (e.g., InSAR-derived surface deformation) and geophysical (electrical resistivity, seismic velocity) constraints on the fault zone and its adjacent shed light on the impact of the physical characteristics of the crustal structure on the inter-seismic loading and surface creep parameters.  This project is funded by the Bogazici University with the BAP Project No SUP-18161.