**Acknowledgements**

in **Table 2**. The regression analysis proposed by Wells and Coppersmith [55] and Johnston [56] shows strong correlation between surface rupture length and magnitude of earthquakes. However the regression analysis shows that probability of occurrence of earthquake magnitude range between 6.3 and 7.3) along F1, magnitude (M 5.4–M 7.3) along F2, magnitude (M 6.1–M 7.3) along F3, magnitude (M 6.7–M 7.3) along F4, magnitude (M 6.0–M 6.6) along F5, magnitude (M 6.7–M 7.3) along F6, magnitude (M 6.7–M 7.2) along F7, magnitude (M 6.2–M 7.2) along F8, magnitude (M 5.6- M 6.7) along F9, magnitude (M 5.6–M 7.0) along F10 respectively (**Table 2**). From the regression analysis it is clear that the faults (F1–F10) passes through the WH are capable for generating earthquake magnitude M 5.4 and M 7.3. Occurrence of February 2006M-5.6 along F9 validates our results and significant level.

Geomorphic indices are widely used to obtain index of active tectonics [25, 48–50]. Here we synthesized conventional geomorphic indices of active tectonics to calculate relative index of active tectonic (RIAT) distribution along the all fault segments (F1–F10). The RIAT classes show that the deformation is higher along the offset zone of fault segment (**Figure 5B**). Conventionally the SL and KS values show abnormal increase of gradient within normal and reverse faults. Minor changes of SL and KS observed within the zone of strike slip fault. At few places the SL and KS values do not shows any variation, which is compared with the strike slip motion of fault. The strike slip motion is well corroborated with the results of seismic tomography and fault plane solution (**Figure 7B**). The existing studies suggest that the terrain close to the GF (F4) experienced occurrence of moderate earthquakes during recent time [23, 27]. The strike slip motion observed from focal mechanism is well correlated with drainage offset along E-W oriented faults within the north and south flowing river system.

Further the observations gathered from the SL, KS and RIAT distribution are corroborated with the geomorphological studies carried out by [23]. The geomorphic expressions such as active fault scarp, shifting and offset of channels indicates that the area is controlled by E-W oriented strike slip faults. Further, steepening of river gradient as observed from tectonic proxy (SL and KS) and uplift of ground further support that the area is tectonically active. Previous studies by [23] suggests that the uplifts in GF zone were associated with interlinking of strike slip fault segments. Further major two phase of tectonic uplift have been identified by [23] based on uplifted fluvial strath terraces. The study shows that the first phase of enhanced uplift took place round 8.0 ± 0.9 ka; however, the second phase of uplift is began after 4 ka and continued till today [23]. In present study, several E-W oriented knickpoints were identified across north and south flowing drainage basins of WH. At several locations these knick points have migrated primarily due to river response to sudden base level fall and secondly incision owing to vertical tectonic forces. As sudden base-level fall can be triggered by tectonic upheaval, climatic change, river capture, or channel incision [87–89]. The incision by river and the formation

of knickpoints are well correlated with tectonic upheaval along F1–F8 (**Figure 2A**).

The study of the topographic configuration morphometric analysis and the subsurface imaging of the fluvial network from WH permitted us to develop a model for the long-term

**11. Conclusions**

150 Tectonics - Problems of Regional Settings

The authors are thankful to Ministry of Earth Science, Government of India (MoES/ P.O.(Seismo)/1(270)/AFM/2015) for financial support under the active fault mapping program. We are thankful to Dr. M. Ravikumar, Director General and Dr. Sumer Chopra, Director, Institute of Seismological Research, Gandhinagar for fruitful discussion.
