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2017 Valparaíso earthquake sequence and the megathrust patchwork of central Chile
Author(s) -
Nealy Jennifer L.,
Herman Matthew W.,
Moore Ginevra L.,
Hayes Gavin P.,
Benz Harley M.,
Bergman Eric A.,
Barrientos Sergio E.
Publication year - 2017
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 - 10.1002/2017gl074767
Subject(s) - seismology , sequence (biology) , geology , foreshock , intraplate earthquake , slip (aerodynamics) , types of earthquake , submarine pipeline , aftershock , geotechnical engineering , tectonics , engineering , genetics , aerospace engineering , biology
Abstract In April 2017, a sequence of earthquakes offshore Valparaíso, Chile, raised concerns of a potential megathrust earthquake in the near future. The largest event in the 2017 sequence was a M 6.9 on 24 April, seemingly colocated with the last great‐sized earthquake in the region—a M 8.0 in March 1985. The history of large earthquakes in this region shows significant variation in rupture size and extent, typically highlighted by a juxtaposition of large ruptures interspersed with smaller magnitude sequences. We show that the 2017 sequence ruptured an area between the two main slip patches during the 1985 earthquake, rerupturing a patch that had previously slipped during the October 1973 M 6.5 earthquake sequence. A significant gap in historic ruptures exists directly to the south of the 2017 sequence, with large enough moment deficit to host a great‐sized earthquake in the near future, if it is locked.