2001 Bhuj-Kachchh earthquake: surface faulting and its relation with neotectonics and regional structures, Gujarat, Western India

J. P. McCalpin, M. G. Thakkar

Abstract


Primary and secondary surface deformation related to the 2001 Bhuj-Kachchh earthquake suggests that thrusting
movement took place along an E-W fault near the western extension of the South Wagad Fault, a synthetic fault
of the Kachchh Mainland Fault (KMF). Despite early reconnaissance reports that concluded there was no primary
surface faulting, we describe an 830 m long, 15-35 cm high, east-west-trending thrust fault scarp near
where the seismogenic fault plane would project to the surface, near Bharodiya village (between 23°34.912'N,
70°23.942'E and 23°34.304'N, 70°24.884'E). Along most of the scarp Jurassic bedrock is thrust over Quaternary
deposits, but the fault scarp also displaces Holocene alluvium and an earth dam, with dips of 13° to 36° south.
Secondary co-seismic features, mainly liquefaction and lateral spreading, dominate the area south of the thrust.
Transverse right-lateral movement along the «Manfara Fault» and a parallel fault near Bharodiya suggests segmentation
of the E-W master faults. Primary (thrust) surface rupture had a length of 0.8 km, maximum displacement
of about 35 cm, and average displacement of about 15 cm. Secondary (strike-slip) faulting was more
extensive, with a total end-to-end length of 15 km, maximum displacement of 35 cm, and average displacement
of about 20 cm.

Keywords


surface rupture;Kachchh earthquake;thrust fault

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References


DOI: https://doi.org/10.4401/ag-3463
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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X