Structural attributes and paleostress analysis of Quaternary landforms along the Vigodi Fault (VF) in Western Kachchh region

Abstract

In this paper, we elucidated deformational and kinematic characteristics of the NW-SE trending Vigodi Fault (VF) and its associated subsidiary faults in the western Kachchh basin. We applied paleostress inversion technique to understand the past stress regime from the acquired fault slip data. The subsidiary faults strike NW-SE and NE-SW and slickensided surfaces are well developed on the Fault planes. We present slip analysis and changes in the stress reorientation using the plane solutions to identify the principal stress axis (σ1) position regionally. To obtain Pressure Tension and Null axis (PBT), stress ratio, and principal (σ1) axis we used the right Dihedron Method using the Win-Tensor and T-Tecto software's respectively. Geomorphologically, the VF zone comprises of bedrock strath terraces towards the upthrown block and fill terraces on the downthrown block of the fault. Development of fault scarps, warped Quaternary sediments, slit canyons within Quaternary sediments, river nick-points, and deflected rivers are the major striking features observed along the strike length of the Vigodi Fault. The analyses indicate that NE-SW compressional stress dominates the regional area and the local area is affected by transpressional stress exhibiting oblique slip motion. The combined observations made from the present investigation can be used to estimate seismic hazard and mitigation planning of the study area.