How InSAR Can Help on the Seismic Hazard Assessment

Abstract

Interferometric synthetic aperture radar (InSAR) is a geodetic technique, particularly utilized to reveal the surface deformation according to its phase differences of two SAR images. Persistent scatterer techniques are a recent development from conventional InSAR and rely on studying pixels, which remains coherent over a sequence of interferograms. These methods can potentially measure mm-scale changes of deformation over spans of ranging from days to years. Accordingly, it allows us to study the spatial and temporal evolution of the crustal deformations. The main contributions of InSAR within the coseismic and interseismic stages of the seismic cycle are particularly in the determination of fault parameters, the distribution and partitioning of strain along faults. Besides, it has also significant contributions to investigate the seismic cycle-related slow crustal deformations, such as postseismic transients and aseismic creep. Postseismic transient signals exhibit characteristic time scales ranging from weeks to decades, which can release ~70% of the moment of the main event. Moreover, some faults slip freely, accumulating little or no strain called as fault creep. Knowledge of the extent and rate of these slow motions of the fault plane are critical for reliable seismic hazard assessments as it effectively reduces the capable area of rupture in earthquakes. Therefore, InSAR has important implications for forecasting the potential earthquakes and for understanding the fault behavior.