TITLE:
Electrical Conductivity and Aftershock Activity in Seismically Active Region of Chamoli, Lesser Himalayas
AUTHORS:
S. Kareemunnisa Begum
KEYWORDS:
Himalayas, Magnetotellurics, Electrical Conductor, Seismicity, Transition Zone
JOURNAL NAME:
Open Journal of Earthquake Research,
Vol.6 No.2,
May
19,
2017
ABSTRACT: The Chamoli earthquake (M6.8) of 29th March 1999 in Himalayan region is one of the recent devastating earthquakes that has killed more than a few hundred lives and caused damage in the vicinity of Chamoli and Gopeshwar districts of Gharwal Himalayan region. A wide band (8192 - 0.008 Hz) magnetotelluric (MT) study has been carried out in the epicentral zone after the earthquake during May-June, 1999 to understand the processes related to tectonic activity. A total of 23 sites were occupied passing through the epicenter along NE-SW and E-W oriented profiles passing through the epicenter. In the present study, the results obtained along NE-SW profile are presented. The deeper electrical structure shows a north-eastward dipping electrical conductor (50 - 100 Ωm) and correlates well with the regional tectonics of the region. Interestingly, the concentration of hypocenters is located at the transition zone of resistor (brittle) and conductor (ductile) at depths of around 10 - 15 km. These results are discussed with reference to the seismotectonics of the region.