LAUSR

In the present study, we assess seismic hazard potential and surface deformation pattern along and across the strike of major active faults in the intra-plate Kachchh Rift Basin (KRB). Towards this, we adopted river Gradient Length Anomaly (GLA) technique, which detects recent tectonic deformation along a river profile on local and regional scales. The major deviations along the river profile can be correlated with exogenic (erosion/sedimentation/anthropogenic) and endogenic (active tectonic movement) processes. We analysed 130 river profiles for GL anomalies, over an area of ~26,700 km 2 in the KRB to identify possible locations that have undergone active tectonic deformation associated with the fault movement. The acquired results show that the higher magnitude negative GL anomalies (uplift) are observed proximal to the fault zones. Our estimates reveal that, around 13% of the study area falls under high tectonically active zone, around 27% of the area falls under moderately active zone, while 60% of the area shows very low or negligible tectonic activity. The estimated results of the GL anomalies are compared with the existing double-difference tomograms, to understand the role of subsurface fault dynamics on the GL anomalies. Furthermore, the results of GLA are correlated with the existing results of the peak ground acceleration (PGA) values of the basin, in order to obtain the precise information regarding surface deformation and site-specific ground acceleration for accurate assessment of seismic hazard.