Surface Creep Rate and Moment Accumulation Rate Along the Aceh Segment of the Sumatran Fault From L‐band ALOS‐1/PALSAR‐1 Observations

Abstract

AbstractWe analyzed the interferometric synthetic aperture radar data from the ALOS‐1/PALSAR‐1 satellite to image the interseismic deformation along the Sumatran fault. The interferometric synthetic aperture radar time series analysis reveals up to ~20 mm/year of aseismic creep on the Aceh segment along the Northern Sumatran fault. This is a large fraction of the total slip rate across this fault. The spatial extent of the aseismic creep extends for ~100 km. The along‐strike variation of the aseismic creep has an inverse “U” shape. An analysis of the moment accumulation rate shows that the central part of the creeping section accumulates moment at approximately 50% of the rate of the surrounding locked segments. An initial analysis of temporal variations suggests that the creep rate may be decelerating with time, suggesting that the creep rate is adjusting to a stress perturbation from nearby seismic activity. Our study has implications to the earthquake hazard along the northern Sumatran fault.