Coseismic and postseismic slip models of the 2011 Van earthquake, Turkey, from InSAR, offset-tracking, MAI, and GPS observations

We derived the coseismic and postseismic slip models of the 2011 Van earthquake from multi-sourcegeodetic datasets, including interferometric synthetic aperture radar (InSAR), multi-aperture InSAR(MAI), offset-tracking, and GPS measurements. The constrained least squares algorithm and Laplaciansmoothing were used to estimate and regularize the slip distribution. The coseismic slip model suggestedtwo nearly W-E striking segment faults breaking during the Van event. Two main slip concentrationswere found to to be located at depths ranging from 7 km to 20 km. The estimated moment reached 6.08 × 1019Nm (equal to an Mw 7.19 event). A stress change analysis showed that the main shock imposedan up to ~5 bars stress load on the causative fault of the 9 November aftershock, implying a triggeringmechanism between the two events. The postseismic slips of the Van earthquake were dominated byshallow left-lateral and deep thrust components. The slips distributed in most of the unruptured area ofthe fault plane. The accumulated postseismic moment reached 2.04 × 1019Nm, which was about 34% ofthe main shock moment. We conclude that the future seismic hazard will be relatively low in this area.