Dynamic Rupture Analysis of Two Northern Chile Earthquakes Mw 6.3 Located in the Double Seismic Zone in the North Of Chile

Different subduction margins have double seismic zones (DSZ), in which it is possible to differentiate two planes of seismicity within the subductant slab. In the case of Chile, several studies have shown the existence of a DSZ in the northern zone. The differences in the dynamic rupture of events located in the upper and lower planes of the DSZ are not well known. In this work we present the results of the study of two intermediate depth earthquakes occurred in northern Chile DSZ. The first event occurred on November 10th, 2017 with a magnitude Mw 6.3 and 94 km depth. The second event occurred on January 21st, 2018 with a magnitude Mw 6.3 and 129 km depth. We relocated mainshocks and their aftershocks. The first event is located at the top of the DSZ and the second inside the Nazca plate. Here we made kinematic and dynamic inversions of these events, to characterize the dynamic parameters that control their rupture. Strong motion records obtained in the near field by the CSN and IPOC networks are used. The events have similarities, such as their dynamic rupture, its duration of approximately 3 s and normal focal mechanisms. However, the behavior of their aftershocks was totally different. The most superficial event presented a large number of aftershocks ( 90) with magnitudes Mw <= 5.0 and on the other hand, the second deepest event presented only one aftershock of Mw 2.0.