International Journal of Earth Sciences

, Volume 99, Supplement 1, pp 265–278

Magnetic fabrics indicating Late Quaternary seismicity in the Himalayan foothills

Authors

  • R. Jayangondaperumal
    • Wadia Institute of Himalayan Geology
    • Wadia Institute of Himalayan Geology
  • B. Senthil Kumar
    • Indian Institute of Sciences
  • S. G. Wesnousky
    • Center for Neotectonic StudiesUniversity of Nevada
  • S. J. Sangode
    • Department of GeologyUniversity of Pune
Original Paper

DOI: 10.1007/s00531-009-0494-5

Cite this article as:
Jayangondaperumal, R., Dubey, A.K., Senthil Kumar, B. et al. Int J Earth Sci (Geol Rundsch) (2010) 99: 265. doi:10.1007/s00531-009-0494-5

Abstract

The anisotropy of magnetic susceptibility (AMS) study was performed on soft sediment samples from a trenched fault zone across the Himalayan frontal thrust (HFT), western Himalaya. AMS orientation of Kmin axes in the trench sediments is consistent with lateral shortening revealed by geometry of deformed regional structures and recent earthquakes. Well-defined vertical magnetic foliation parallel to the flexure cleavage in which a vertical magnetic lineation is developed, high anisotropy, and triaxial ellipsoids suggest large overprinting of earthquake-related fabrics. The AMS data suggest a gradual variation from layer parallel shortening (LPS) at a distance from the fault trace to a simple shear fabric close to the fault trace. An abrupt change in the shortening direction (Kmin) from NE–SW to E–W suggests a juxtaposition of pre-existing layer parallel shortening fabric, and bending-related flexure associated with an earthquake. Hence the orientation pattern of magnetic susceptibility axes helps in identifying co-seismic structures in Late Holocene surface sediments.

Keywords

Anisotropy of magnetic susceptibility (AMS)Earthquake fabricHimalayaPaleoseismicity

Copyright information

© Springer-Verlag 2009