Ehsan Kosari , Sabrina Metzger, Victor Navarro-Sanchez, Onno Oncken, Bernd Schurr, Matthias Rosenau

Along-strike seismotectonic behavior of subduction megathrusts feeds back into the forearc deformation as elastic and permanent deformation. However, whether and how short-term elastic deformation reflects long-term permanent deformation in the forearc and shapes the coastal region remains unclear. To evaluate the forearc deformation, we analyze the interseismic surface deformation obtained from six years of Sentinel-1 InSAR time series along the North Chilean Forearc (between 21.5°S to 26°S latitude), a hyperarid region where erosional processes masking topographic signals are minimized. To assess the conversion of interseismic vertical deformation into permanent deformation, we examine the spatial correlation between geodetic (short-term) vertical deformation and geomorphic (long-term) uplift markers and topography along the coast and Coastal Cordillera. Our findings reveal that the correlation between geodetic uplift rates and long-term uplift markers becomes neutral at the Mejillones Peninsula, suggesting localized tectonic activity. The Peninsula also separates two distinct seismotectonic segments with differing deformation patterns in the North and South. In the Northern segment, correlations and anticorrelations between geodetic uplift rates and geomorphic features imply episodic uplift, while upper plate faults exhibit less strain accumulation compared to the Southern segment and the Peninsula. The correlation variation may result from short-term, short-wavelength processes, while the consistently positive correlations with topography likely reflect long-term, long-wavelength deformation, overshadowing seismic-cycle short-wavelength deformation.