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Coseismic slip and afterslip of the 2015 M w 8.3 Illapel (Chile) earthquake determined from continuous GPS data
Author(s) -
Shrivastava Mahesh N.,
González Gabriel,
Moreno Marcos,
Chlieh Mohamed,
Salazar Pablo,
Reddy C. D.,
Báez Juan Carlos,
Yáñez Gonzalo,
González Juan,
Llera Juan Carlos
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070684
Subject(s) - geology , aftershock , seismology , slip (aerodynamics) , subduction , seismic moment , earthquake rupture , geodesy , ridge , fault (geology) , tectonics , paleontology , physics , thermodynamics
We analyzed the coseismic and early postseismic deformation of the 2015, M w 8.3 Illapel earthquake by inverting 13 continuous GPS time series. The seismic rupture concentrated in a shallow (<20 km depth) and 100 km long asperity, which slipped up to 8 m, releasing a seismic moment of 3.6 × 10 21 Nm ( M w = 8.3). After 43 days, postseismic afterslip encompassed the coseismic rupture. Afterslip concentrated in two main patches of 0.50 m between 20 and 40 km depth along the northern and southern ends of the rupture, partially overlapping the coseismic slip. Afterslip and aftershocks confined to region of positive Coulomb stress change, promoted by the coseismic slip. The early postseismic afterslip was accommodated ~53% aseismically and ~47% seismically by aftershocks. The Illapel earthquake rupture is confined by two low interseismic coupling zones, which coincide with two major features of the subducting Nazca Plate, the Challenger Fault Zone and Juan Fernandez Ridge.