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Paleo-earthquake signatures from the South Wagad Fault (SWF), Wagad Island, Kachchh, Gujarat, western India: A potential seismic hazard.
- Source :
-
Journal of Structural Geology . Feb2017, Vol. 95, p142-159. 18p. - Publication Year :
- 2017
-
Abstract
- In last 500 years, Kachchh experienced several large magnitude earthquakes (6.0 ≥ M ≤ 7.8), however, not all accompanied surface rupture. The 1819 Allah Bund earthquake (Mw7.8) accompanied surface rupture, whereas, the 2001 Bhuj event (Mw7.6) occurred at a depth of 23 km on E-W striking south dipping thrust fault remained blind. Discontinuities between the denser-brittle basement (?) and overlying ductile-softer Mesozoic-Tertiary-Quaternary succession resulted in a different geometry of faulting. Normal faults associated with rift were reactivated as reverse faults during inversion tectonics, propagated in sedimentary succession and arrested. Thrust-ramps developed along the discontinuities accompanied surface ruptures. Folded structures along the South Wagad Fault (SWF) – an active thrust, exhibits lateral-propagation of fold segments and linkage, suggestive of fault-related-fold growth. Paleoseismic investigations revealed evidence of at least three paleo-earthquakes. Event I occurred before BCE 5080; Event II between BCE 4820 and 2320, and was probably responsible for a massive damage at Dholavira – Harappan site. Event III was between BCE 1230 and 04, most likely caused severe damage to Dholavira. Archaeo-seismological Quality Factor (AQF) of 0.5 suggests that the Dholavira is vulnerable to earthquakes from nearby active faults. With 1500–2000 yr of recurrence interval, occurrence of a large magnitude earthquake on SWF cannot be ruled out. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01918141
- Volume :
- 95
- Database :
- Academic Search Index
- Journal :
- Journal of Structural Geology
- Publication Type :
- Academic Journal
- Accession number :
- 121222278
- Full Text :
- https://doi.org/10.1016/j.jsg.2016.12.011