Early Stage and Main Ruptures of the 2015 Mw8.3 Illapel, Chile, Megathrust Earthquake: Kinematic Elliptical Inversions and Dynamic Rupture Simulations

We apply kinematic and dynamic modeling to the 2015 Mw8.3 Illapel, Chile, earthquake constrained by continuous high-rate GPS strong motion data. Kinematic inversion elliptical patches allows us rapidly outline ruptured area with different time windows frequency ranges. The preferred solution indicates that main large patch in north is preceded a small one south close hypocenter shift no greater than 20 s. rupture directivity on suggests origin at depth, away from initial hypocentral patch. then construct models be consistent geometry obtained inversion. estimate fracture energy of ∼7.5 MJ/m2. does not trigger due gap energy, thus another nucleation set depth. This can regarded as foreshock-mainshock sequence rather direct cascade growth. corresponds preexisting zone interseismic coupling prior Illapel earthquake. historical seismicity previous century possible reconstruction asperity map, assuming every represents characteristic seismogenic Therefore, construction ruptures geodetic seismological knowledge useful only for reproducing known earthquakes but also providing physically model quantitative seismic hazard study.