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 K min 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 (K min) 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 fabric Himalaya Paleoseismicity

Copyright information

© Springer-Verlag 2009