Geoscience Reference
In-Depth Information
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
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