Record Details

Luminescence chronometry and geomorphic evidence of active fold growth along the Kachchh Mainland Fault (KMF), Kachchh, India: Seismotectonic implications

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title Luminescence chronometry and geomorphic evidence of active fold growth along the Kachchh Mainland Fault (KMF), Kachchh, India: Seismotectonic implications
 
Creator MATHEW, G
SINGHVI, AK
KARANTH, RV
 
Subject 2001 bhuj earthquake
san-joaquin valley
stream response
thar desert
california
kutch
reactivation
deformation
chronology
himalayas
kachchh
kutch
bhuj
uplift
earthquake
active tectonics
optical dating
 
Description The Kachchh region of Western India is a pericratonic basin experiencing periodic high magnitude earthquakes events. In 2001 a catastrophic seismic event occurred at Bhuj measuring M-w=7.7. The epicenters of both the 1956 and 2001 earthquakes were along the Kachchh Mainland Fault (KMF), proximal to the eastern end of the Northern Hill Range (NHR). The latter is a topographic expression of an active fault related fold on the hanging wall, and is controlled by a south dipping blind thrust. The present study deals with the eastern sector of NHR and uses optical dating to reconstruct the chronology of tectonically caused incisions. Along the backlimb of the NFIR, incision ages on, channel fills and valley fill terraces progressively decrease from similar to 12 ka to 4.3 ka. This age progression along with geomorphic evidences (decrease in topographic relief, drainage capture and drainage migration across the fold nose) suggests an active vertical and lateral fold growth along the KMF. Optical ages suggest that during the Late Holocene, the average uplift rate along the eastern NHR was 10 +/- 1 mm/a. Recent GPS based estimates on crustal shortening are similar to 12 mm/a. The KMF and the South Wagad Fault (SWF) represent the bounding faults of a transtensional basin that formed during the initial rifling. This basin is termed as the Samakhiali basin. The compressive stresses on account of structural inversion from normal to reverse phase resulted in lobate-shaped anticlines along KMF and SWF zone. These anticlines subsequently coalesced and formed linked and overlap segments. The present study suggests that eastward lateral deformation across the eastern portion of KMF has continued and has now resulted in its interaction with a left step over transfer fault called the;South Wagad Master Fault (SWMF). This implies an increasing transpersional deformation of the Samakhiali basin. We therefore, suggest that the eastward NFIR ridge propagation along KMF resulted in the thrust faulting on the south dipping SWMF resulting in the Bhuj 2001 event. The increasing strain on this basin may cause enhanced seismicity in the future along the eastern KMF and Wagad region. (c) 2006 Elsevier B.V .
 
Publisher ELSEVIER SCIENCE BV
 
Date 2011-07-25T16:37:07Z
2011-12-26T12:51:31Z
2011-12-27T05:37:03Z
2011-07-25T16:37:07Z
2011-12-26T12:51:31Z
2011-12-27T05:37:03Z
2006
 
Type Article
 
Identifier TECTONOPHYSICS, 422(1-4), 71-87
0040-1951
http://dx.doi.org/10.1016/j.tecto.2006.05.009
http://dspace.library.iitb.ac.in/xmlui/handle/10054/6735
http://hdl.handle.net/10054/6735
 
Language en