26 October 2020

Introduction:

The suture zone of the Himalayas or the Indus Suture Zone (ISZ) in the Ladakh region where Indian and Asian Plates are joined, has been found to be tectonically active.

Highlights of the study:

• A group of Scientists from Wadia Institute of Himalayan Geology (WIHG), Dehradun, an autonomous institute under the Department of Science and Technology, Government of India, have found through observations and detail mapping of geological features that the suture zone of Himalaya that was conventionally thought to be locked is tectonically active.
•  They carried out the mapping of the remote regions of Ladakh that forms the most hinterland part of the Himalaya.
• The study was published recently in the journal ‘Technophysics’.
• The scientists have observed that the thrust is broken, sedimentary beds are tilted.
• Bedrocks are showing brittle deformation and the rivers are associated with the uplifted terraces.
• The scientists used the technique of Optically Stimulated Luminescence to make these observations.
• The findings say that the Suture Zone of the Himalayas has been active in the recent years of the earth history. This is one of the reasons for recent earthquakes in India.
• The scientists have estimated it as 78,000 to 58,000 years.
•  According to them, the recent 2010 earthquake of low magnitude 4.0 in the village of Upshi was due to thrust rupture.

 About the Himalayan Thrusts

• Himalayas are made of three thrusts namely:
•  Main Central Thrust,
•  Main Frontal Thrust and
• Main Boundary Thrust.
•  According to the study, Main Frontal Thrusts are locked and the overall deformation is occurring in the Main Frontal Thrust.
• The study also says that there is a remote fault zone in the suture zone that is tectonically active.

What are Thrusts?

• Thrusts are faults. Faults are gently curved or fractures in the rocks of the Earth’s crust.

What are Suture Zones?

• It is joining together of two fault zones. I
• t is usually found in mountain ranges.

What is Himalayan Suture Zone?

• It is also called Indus Suture Zone or Indus Yarlung Tsangpo Suture Zone.
• It is the zone of the collision between the Indian Plate and the Ladakh Batholith.

Tectonic Activity in the Suture Zone.

• The Ladakh plateau and the Karakoram range lie to the north of the Indus Suture Zone.
• They are originally formed as a part of the European plate.
• This zone has now become active according to the study.

While the regions of Jammu and Kashmir, Uttarakhand