Newly identified tectonically active zone in the Himalayas:
The Indus Suture Zone (ISZ) or the suture zone of the Himalayas in the Ladakh region where Indian & Asian Plates are joined has been found to be tectonically active, as against current understanding that it is a locked zone. This may have major implications in terms of earthquake study, prediction, understanding the seismic structure of the mountain chains well as its evolution.
Highlights:
♦ Scientists from WIHG -Wadia Institute of Himalayan Geology, Dehradun, an autonomous institute under the Department of Science and Technology (DST), Government of India, have found through observations and detailed mapping of geological features that the Indus Suture Zone that was thought to be locked is tectonically active.
♦ Scientists have done the mapping of the remote regions of Ladakh region that forms the most hinterland part of the Himalaya.
♦ The geologists analysed that sedimentary beds are tilted & thrust broken, the rivers are associated with uplifted terraces, and the bedrock shows brittle deformation that occurred at much shallower depths.
♦ The combination of lab and field data suggested the region of the ISZ - Indus Suture Zone has been neo-tectonically active since the last 78000 -- 58000 years and a recent earthquake in 2010 of low magnitude 4.0 near the village of Upshi that occurred due to a thrust rupture.
♦ Himalayas were made up of north dipping thrusts like the MCT - Main Central Thrust, MBT - the Main Boundary Thrust, MFT - the Main Frontal Thrust.
♦ As per the established models, all of these thrusts except MFT are locked, and overall deformation in Himalaya is being accommodated only along with the MFT.
♦ The new findings, which suggest a more remote fault at the suture zone being neo-tectonically active, could call for a serious relook into the existing evolutionary models using new techniques and a larger geological database.