ISSN:
1420-9136
Keywords:
Intraplate stresses
;
intraplate seismicity
;
linear belts
;
stable region
;
pre-existing faults
;
pore pressure
;
stress amplification
;
reactivation mechanisms
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract Intraplate stresses and intraplate seismicity in the Indian subcontinent are strongly affected by the continued convergence between India and Eurasia. The mean orientation of the maximum horizontal compression in the Indian subcontinent is subparallel to the direction of the ridge push at the plate boundary as well as to the direction of compression expected to arise from the net resistive forces at the Himalayan collision zone, indicating that the intraplate stresses in the subcontinent, including the shield area, are caused by plate tectonic processes. Spatial distribution of historic and instrumentally recorded earthquakes indicate that the seismic activity is mostly confined to linear belts while the remaining large area of the shield is stable. The available conventional heat flow data and other indicators of heat flow suggest hotter geotherms in the linear belts, leading to amplification of stresses in the upper brittle crust. Many of the faults in these linear belts, which happen to be 200–80 m.y. old, are being reactivated either in a strike-slip or thrust-faulting mode. The reactivation mechanisms have been analyzed by taking into consideration the amplification of stresses, pore pressures, geological history of the faults and their orientation with respect to the contemporaneous stress field. The seismicity of the Indian shield is explained in terms of these reactivation mechanisms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00874731
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