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The Kachchh Basin, located in Gujarat (India) at the western trailing edge of the Indian plate, comprises several east–west trending seismically active faults. The Kachchh Basin evolved in two major stages. The first is the rift stage, which correlates with the break-up and separation of the Indian plate in the Late Triassic–Early Cretaceous and synrift sedimentation. The second is the post-Deccan Trap inversion stage, when the basin was periodically uplifted along the existing east–west trending intrabasinal master faults: the Katrol Hill Fault, the Kachchh Mainland Fault, the South Wagad Fault, the Gedi Fault and the Island Belt Fault. The inversion of basin was initiated by the onset of a compressive stress regime in response to the collision of the Indian plate with the Eurasian plate in the far north during the Early Eocene. This is shown by the tilting of the Deccan Trap lava flows along with the underlying Mesozoic sequence and the associated intrusive bodies that occupy the core portions of domal and anticlinal flexures bounded by major fault lines. Seismotectonic data on the prolonged aftershock sequence after the 2001 Bhuj earthquake (Mw 7.7) reveal continuous low-to-moderate seismic activity along multiple faults covering a large area, now identified as the Kachchh Seismic Zone. This article reviews the neotectonic perspective of the active faults with the prime objective of delineating the post-Deccan Trap inversion phase of the Kachchh Basin, with an emphasis on neotectonism with regard to modern seismic activity. The datasets presented are primarily field-based neotectonic data from active fault zones that cover aspects of the tectonic geomorphology, Quaternary stratigraphy, near-surface fault traces and the nature of the fault in the shallow subsurface based on ground-penetrating radar studies. We also attempt a comparative neotectonic evaluation of each active fault in the Kachchh Basin and discuss the constraints for evolving a viable neotectonic model of the basin.

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Kachchh possesses a fault-controlled first-order topography and several geomorphic features indicative of active tectonics. Though coseismic neotectonic activity is believed to be the major factor in the evolution of the landscape, detailed documentation and analysis of vital landscape features like drainage characteristics, bedrock gorges and terraces are lacking. The present study is a site-specific documentation of gorges developed in the central part of the mainland Kachchh. We analyzed and interpreted four gorges occurring on either side of Katrol Hill Fault (KHF). The Khari river gorge is endowed with six levels of bedrock terraces, some of which are studded with large potholes and flutings. Since no active development of potholes is observed along the rivers in the present day hyper-arid conditions, we infer an obvious linkage of gorges to the humid phases, which provided high energy runoff for the formation of gorges and distinct bedrock terraces and associated erosional features. Development of gorges within the miliolites and incision in the fluvial deposits to the south of the KHF indicates that the gorges were formed during Early Holocene. However, ubiquitous occurrence of gorges along the streams to the south of KHF, the uniformly N40 • E trend of the gorges, their close association with transverse faults and the short length of the exceptionally well developed Khari river gorge in the low-relief rocky plain to the north of KHF suggests an important role of neotectonic movements.