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Himalayan Geology, Vol.
30 (2), 2009, pp.133-137 Printed in India
Seasonal variations observed in
seismicity of the NW Himalaya, India
SUSHIL KUMAR, SUNDEEP CHABAK
Wadia Institute of Himalayan
Geology, Dehra Dun - 248001, India
Abstract:
We report here preliminary
observations about seasonal stress and strain variations in the NW Himalaya,
induced by water storage variations which correlate with seasonal variations
of seismicity. The seismicity rate is observed twice as high in the winter
as in the summer. Stresses and pore pressure due to natural processes may
already have accumulated in crustal rocks after monsoon season in the High
to frontal foothill regions to near critical levels for fresh faulting or
renewed slip on pre-existing faults. The stresses and pore pressure induced
by overloading of water after the monsoon season may explain the tendencies
to such failures and trigger or induce large number of earthquakes |
