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Seismic slip deficit in the Kashmir Himalaya from GPS observations
Author(s) -
Schiffman Celia,
Bali Bikram Singh,
Szeliga Walter,
Bilham Roger
Publication year - 2013
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 - 10.1002/2013gl057700
Subject(s) - geology , seismology , slip (aerodynamics) , episodic tremor and slip , sinistral and dextral , slow earthquake , seismic moment , thrust fault , décollement , fault (geology) , geodesy , moment magnitude scale , global positioning system , subduction , interplate earthquake , tectonics , geometry , telecommunications , physics , computer science , thermodynamics , mathematics , scaling
GPS measurements in Kashmir Himalaya reveal range‐normal convergence of 11 ± 1 mm/yr with dextral shear of 5 ± 1 mm/yr. The transition from a fully locked 170 km wide décollement to the unrestrained descending Indian plate occurs at ~25 km depth over an ~23 km wide transition zone. The convergence rate is consistent with the lower bounds of geological estimates for the Main Frontal Thrust, Riasi, and Balapora fault systems, on which no surface slip has been reported in the past millennium. Of the 14 damaging Kashmir earthquakes since 1123, none may have exceeded M w = 7.6. Therefore, either a seismic moment deficit equivalent to a M w ≈ 8.7 earthquake exists or the historical earthquake magnitudes have been underestimated. Alternatively, these earthquakes have occurred on reverse faults in the Kashmir Valley, and the décollement has been recently inactive. Although this can reconcile the inferred and theoretical moment release, it is quantitatively inconsistent with observed fault slip in Kashmir.