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Geological structures control on earthquake ruptures: The M w 7.7, 2013, Balochistan earthquake, Pakistan
Author(s) -
Vallage A.,
Klinger Y.,
Lacassin R.,
Delorme A.,
PierrotDeseilligny M.
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 - 10.1002/2016gl070418
Subject(s) - geology , seismology , fault (geology) , context (archaeology) , subduction , earthquake rupture , deformation (meteorology) , azimuth , geodesy , tectonics , displacement (psychology) , geometry , psychology , paleontology , oceanography , mathematics , psychotherapist
Abstract The 2013 M w 7.7 Balochistan earthquake, Pakistan, ruptured the Hoshab fault. Left‐lateral motion dominated the deformation pattern, although significant vertical motion is found along the southern part of the rupture. Correlation of high‐resolution (2.5 m) optical satellite images provided horizontal displacement along the entire rupture. In parallel, we mapped the ground rupture geometry at 1:500 scale. We show that the azimuth of the ground rupture distributes mainly between two directions, N216° and N259°. The direction N216° matches the direction of preexisting geologic structures resulting from penetrative deformation caused by the nearby Makran subduction. Hence, during a significant part of its rupture, the 2013 Balochistan rupture kept switching between a long‐term fault front and secondary branches, in which existence and direction are related to the compressional context. It shows unambiguous direct interactions between different preexisting geologic structures, regional stress, and dynamic‐rupture stress, which controlled earthquake propagation path.