Seismotectonics of the Kachchh Region

The Kachchh region of western India occupies a key position within the Indian plate’s intraplate domain, hosting a complex network of reverse and strike-slip faults beneath a predominantly alluvial cover. Major historic earthquakes, notably the 1819 Mw 7.8 Allah Bund event and the 2001 Mw 7.6 Bhuj rupture, attest to its capacity for large­-magnitude seismicity despite low to moderate strain rates measured by geodetic networks. Active structures include the Kachchh Mainland Fault system, the north-verging Jhura fault beneath the Jhura anticline, and the east–west–trending Island Belt Fault and associated uplift blocks. These buried faults manifest through fold scarps, fault-bounded terraces and linear geomorphic contrasts, while modern deformation is revealed by GPS-derived strain accumulation and interferometric synthetic aperture radar. Paleoseismic trenching has identified multiple Holocene surface-rupturing events, pointing to recurrence intervals of several millennia and underscoring significant seismic hazard. Improved characterisation of individual fault segments, informed by integrated geomorphology, palaeoseismology and geodesy, is crucial for refining seismic-hazard models in this densely populated and infrastructure-sensitive landscape. The Kachchh case also offers a global analogue for understanding intraplate seismic systems where concealed fault geometries and long earthquake recurrence demand multidisciplinary investigation and targeted risk mitigation.

Research from Nature Portfolio

Recent palaeoseismic investigations have revealed three distinct surface-rupturing earthquakes along a segment of the Jhura fault beneath the Jhura anticline, bracketing events at ca. 9.7 ka, 8.4 ka and 6.1 ka before present. The absence of younger displacements implies a prolonged quiescent interval exceeding 8,000 years, suggesting accumulation of significant elastic strain and elevated current seismic hazard. Detailed trench logging and sediment dating have refined slip rates and fault segmentation, enabling recalibration of probabilistic seismic-hazard assessments for the southern margin of the Great Rann of Kachchh. This work emphasises the need for fault-specific characterisation within intraplate settings where surface expression is subdued by rapid sedimentation and where long recurrence intervals obscure the palaeoseismic record.

Seismotectonics of the Kachchh Region publication trend

The graph below shows the total number of articles in seismotectonics of the kachchh region across all publications each year (not limited to Nature Index journals).

Technical terms

Seismotectonics: Study of the relationship between seismicity and tectonic structures.
Paleoseismology: Investigation of prehistoric earthquakes via geological trenching and sediment dating.
Fault scarp: A steep slope or cliff formed by displacement along a fault plane.
Stream power incision index (Ksn): A quantitative measure of channel steepness sensitive to tectonic uplift.
Interferometric Synthetic Aperture Radar (DInSAR): Remote-sensing technique for mapping ground deformation over time.

References

1. Holocene surface-rupturing paleo-earthquakes along the Kachchh Mainland Fault: shaping the seismic landscape of Kachchh, Western India. Scientific Reports (2024).
2. Delineation of tectonically active zones in the Island Belt Uplift region, Kachchh Basin, western India: A geomorphic and geodetic approach. Quaternary Science Advances (2021).
3. Hydraulically conductive fault zone responsible for monsoon triggered earthquakes in Talala, India. Tectonophysics (2021).