Detecting active faults in intramountain basins using Electric Resistivity Tomography

Hamid Sana, Petr Taborik, Fayaz A. Bhat, Jan Flašar, & Petra Stepancikova

Published August 15, 2019, SCEC Contribution #9700, 2019 SCEC Annual Meeting Poster #113

Kashmir basin in the NW Himalaya is surrounded by main Himalayan boundary faults, has very well documented historical earthquakes and a good instrumental earthquake record. However, the causative faults of these earthquakes except the 8 October 2005 Kashmir earthquake (M7.6) are not known. One of many historical earthquakes that have struck and caused damage and destruction in the Kashmir basin is the 30 May 1885 Kashmir earthquake (~M6.3). The extensive damage due to this earthquake was reported in the NW part of the basin and as usual the causative fault is not known and mapped. As the earthquake related geomorphic features are not preserved due to the high erosion rates. We mapped certain active fault strands using high resolution digital elevation models (DEM), later complemented by the field investigation in the NW Kashmir. The Electric Resistivity Tomography (ERT) was carried out at certain identified sites in the macroseismic epicentral area of the 1885 Kashmir earthquake. The results show a significant active normal fault which was named as the NW Kashmir fault. The ERT results were confirmed by excavating a trench and an already dug trench to construct a building at the ERT sites. This fault is most likely the causative fault of the 30 May 1885 Kashmir earthquake (work under progress). The results show that ERT is a very useful shallow geophysical method to detect faults in the Karewas. Karewas are the Plio-Pleistocene and Holocene (reworked by rivers), fluvio-lacustrine, soft and unconsolidated, sand-clay-conglomerate sediments, deposited as distinct table-land geomorphic features in the Kashmir basin which are significantly water saturated.

Key Words
Active Tectonics, Electric Resistivity Tomography, Kashmir basin, NW Himalaya

Citation
Sana, H., Taborik, P., Bhat, F., Flašar, J., & Stepancikova, P. (2019, 08). Detecting active faults in intramountain basins using Electric Resistivity Tomography . Poster Presentation at 2019 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Geology