The 1 April 2014 Iquique, Chile, M 8.1 earthquake rupture sequence (original) (raw)

On 1 April 2014, a great (M w 8.1) interplate thrust earthquake ruptured in the northern portion of the 1877 earthquake seismic gap in northern Chile. The sequence commenced on 16 March 2014 with a magnitude 6.7 thrust event, followed by thrust-faulting aftershocks that migrated northward~40 km over 2 weeks to near the main shock hypocenter. Guided by short-period teleseismic P wave backprojections and inversion of deepwater tsunami wave recordings, a finite-fault inversion of teleseismic P and SH waves using a geometry consistent with long-period seismic waves resolves a spatially compact large-slip (~2-6.7 m) zone located~30 km downdip and~30 km along-strike south of the hypocenter, downdip of the foreshock sequence. The main shock seismic moment is 1.7 × 10 21 N m with a fault dip of 18°, radiated seismic energy of 4.5-8.4 × 10 16 J, and static stress drop of~2.5 MPa. Most of the 1877 gap remains unbroken and hazardous.