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Fault creep rates of the Chaman fault (Afghanistan and Pakistan) inferred from InSAR
Author(s) -
Barnhart William D.
Publication year - 2017
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb013656
Subject(s) - interferometric synthetic aperture radar , geology , seismology , fault (geology) , slip (aerodynamics) , geodesy , sinistral and dextral , seismic gap , creep , fault trace , fault scarp , synthetic aperture radar , remote sensing , physics , materials science , composite material , thermodynamics
The Chaman fault is the major strike‐slip structural boundary between the India and Eurasia plates. Despite sinistral slip rates similar to the North America‐Pacific plate boundary, no major (> M 7) earthquakes have been documented along the Chaman fault, indicating that the fault either creeps aseismically or is at a late stage in its seismic cycle. Recent work with remotely sensed interferometric synthetic aperture radar (InSAR) time series documented a heterogeneous distribution of fault creep and interseismic coupling along the entire length of the Chaman fault, including an ~125 km long creeping segment and an ~95 km long locked segment within the region documented in this study. Here I present additional InSAR time series results from the Envisat and ALOS radar missions spanning the southern and central Chaman fault in an effort to constrain the locking depth, dip, and slip direction of the Chaman fault. I find that the fault deviates little from a vertical geometry and accommodates little to no fault‐normal displacements. Peak‐documented creep rates on the fault are 9–12 mm/yr, accounting for 25–33% of the total motion between India and Eurasia, and locking depths in creeping segments are commonly shallower than 500 m. The magnitude of the 1892 Chaman earthquake is well predicted by the total area of the ~95 km long coupled segment. To a first order, the heterogeneous distribution of aseismic creep combined with consistently shallow locking depths suggests that the southern and central Chaman fault may only produce small to moderate earthquakes (< M 7).