Rupture Process and Strong-Motion Generation of the 2014 Iquique, Northern Chile, Earthquake

Abstract

To investigate the rupture process and strong-motion generation of the [Formula: see text] 8.2 Iquique, Northern Chile, earthquake in 2014, we estimated kinematic source models from waveform inversion and back-projection analyses using strong-motion records. A slip model derived from the waveform inversion using the low-frequency (0.02–0.125[Formula: see text]Hz) velocities is characterized by a large slip area localized 50[Formula: see text]km south of the epicenter with a peak slip of 10[Formula: see text]m, and a deeper slip area with a peak slip above 2[Formula: see text]m located below the coast. The main rupture of these areas started 25[Formula: see text]s after the initial break generating two pronounced phases observed in most of the records. The landward slip area ruptured for about 10[Formula: see text]s generating the first impulsive phase, while the offshore largest slip area ruptured for 20[Formula: see text]s creating a longer duration phase observed later. Results from a back-projection analysis based on stacking of envelopes of 5–10-Hz accelerations indicate that the high-frequency radiation propagated down-dip towards the coast, reaching its maximum value from 25[Formula: see text]s to 40[Formula: see text]s, far away from the shallow main slip area obtained from low-frequency waveform inversion. Our results suggest a clear depth dependence of the seismic wave radiation during the Iquique earthquake.