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Figure 6.16 Composite map of resultant displacement of two GPS sites (DHAM-DUDH (upper
curve) and RATN-GIBF (lower curve) plotted with respect to ISRG from 14 days to 8 years after
the 2001 Bhuj earthquake. DHAM and RATN are two GPS stations of Reddy and Sunil ( 2008 )
co-located with DUDH and GIBF of the ISR stations, respectively. The displacement decay rate for
the upper curve is D = 7.6 ln( t ) + 20.36, for the lower curve D = 5.8 ln( t ) + 10.22. The number of
shocks of M w
4 along the SWF are also shown. The strain calculated in the Kachchh region during
2008-11 along the baselines, as shown in the inset, is representative of the strain in most parts of the
active area. For 2005-7 the strain is likely to be greater than that for the period 2008-11 due to the
larger displacements.
6.5 Focal mechanism studies
The focal mechanisms for nine significant events (M w 4.0-5.6) by full waveform moment
tensor inversion (10-20 s) reveal a dominant reverse movement with minor strike-slip
component on the south-dipping NWF, indicating continued thrusting in the 2001 rupture
zone. The 2006 mainshock of M w 5.6 on the Gedi fault reveals a left-lateral strike-slip
movement on an almost vertical fault, but the two aftershocks of M 4-5 indicate a greater
thrust component (Mandal et al ., 2009 ; Nagabhushana Rao, 2012). It appears that the
 
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