The Himalayas could experience major earthquakes, according to new findings by a team of researchers at the National Geophysical Research Institute (NGRI) in Hyderabad and Stanford University in the US. The study was published in the recently-released Nature India journal.
Their inference is based on seismic imaging of the region below Garhwal Himalayas. Seismic imaging - somewhat similar to medical imaging - is a geophysical technique to investigate sub-surface structures from measurements made at the surface.
The Himalayan range was formed, and remains active due to the collision of the Indian and Asian continental plates initiated around 50 million years ago. "This convergence is manifested by shortening across the Himalaya, building up of strain and occurrence of great earthquakes," Shyam Rai, chief scientist of NGRI and project leader of the Indian team told Nature India.
While scientists know that India is sub ducting under Asia, they have started studying in great detail the complexity of this collision zone recently - particularly about the Main Himalayan Thrust (MHT), the fault that separates the Indian continental plate from the Asian plate. The MHT has historically been responsible for a magnitude 8 to 9 earthquake every several hundred years.
The researchers seismically imaged the sub ducting Indian plate in a transect across the Garhwal Himalaya, and related this image to the seismicity, geomorphology and tectonics of the collision zone.
Seismic images of the MHT created by the Stanford-NGRI group reveal that deformation in the Himalaya is localised on MHT.