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Seismotectonic implications of strike-slip earthquakes in the Darjiling-Sikkim Himalaya

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Title Seismotectonic implications of strike-slip earthquakes in the Darjiling-Sikkim Himalaya
 
Creator MUKUL, M
JADE, S
ANSARI, K
MATIN, A
 
Subject Darjiling-Sikkim Himalaya
dislocation modelling
Global Positioning System
Gish Transverse Fault
recess
salient
seismicity
SEISMIC HAZARD
SEPTEMBER 2011
THRUST BELT
NEPAL HIMALAYA
COLLISION ZONE
FORELAND BASIN
EASTERN NEPAL
SUB-HIMALAYA
INDIA
GEOMETRY
 
Description The Darjiling-Sikkim Himalaya (DSH) is located over the Dharan-Gorubathan salient recess pair and moderate thrust and strike slip earthquake occur here. The hypocentres cluster not only near the location of the Main Himalayan Thrust (MHT) or the basal decollement of the Himalayan wedge, but also well above and below it. The epicentres cluster over the mapped location of the Lesser Himalayan Duplex (LHD), suggesting that both MHT and LHD are active structures in DSH. The earthquakes below MHT can be related to transverse strike slip faulting in DSH associated with salient recess transition on both flanks of the Dharan salient. The 18 September 2011 (Mw 6.9) strike slip event suggests that the western flank of the Dharan salient is also likely to contain an active transverse strike slip fault like the Gish Transverse Fault (GTF) on its eastern flank. High-precision Global Positioning System measurements (1997-2006) indicate that a maximum of similar to 4 mm/year convergence is being accommodated in the Tista Half-Window or LHD west of the surface trace of GTF and DSH is locked south of 27 degrees N both east and west of GTF about 10 km north of the Himalayan mountain front. About 3-4 mm/year sinistral strike slip is postulated on GTF north of 27 degrees N. Dislocation based forward modelling using two thrust dislocations with oblique slip and a sinistral strike slip dislocation generated velocities that were closest to the measured back-slip velocity field in DSH.
 
Publisher INDIAN ACAD SCIENCES
 
Date 2014-12-29T06:40:59Z
2014-12-29T06:40:59Z
2014
 
Type Article
 
Identifier CURRENT SCIENCE, 106(2)198-210
0011-3891
http://dspace.library.iitb.ac.in/jspui/handle/100/17334
 
Language English