Arunachal region highly prone to seismic trigger, says NGRI study

HYDERABAD: Even tiny stresses can cause seismic triggering in the Arunachal Pradesh region, says a study by Hyderabad-based National Geophysical Research Institute (NGRI).
NGRI scientists, who investigated dynamic triggering in Arunachal using data of 34 significant remote and distant earthquakes, have identified triggered seismicity in the form of microearthquakes and non-volcanic tremors during six remote mainshocks.Arunachal Pradesh, located in north-east India, falls in a seismically active zone.

Abhey Ram Bansal, one of the authors of the study, titled ‘Tiny stresses are capable of triggering earthquakes and tremors in Arunachal Himalaya’ published in Scientific Reports journal, said, “The region is highly vulnerable to seismic activities due to its location at the collision zone of Indian and Eurasian tectonic plates. The area is prone to earthquakes because of the complex structure of faults and fractures. The region is also well known for the complexity of its geological characteristics.”
Speaking to TOI, Tony Saini, the lead researcher, said that he plans to carry out a study for the whole Himalayan belt, which will help find stress thresholds and identify sensitive regions there. Bansal said: “Static, quasi-static and dynamic stresses are vital in triggering earthquakes in an area. We have studied seismic triggering while passing large earthquakes’ surface waves, which occurred in faraway places. This triggering is known as dynamic triggering or remote triggering.” CSIR-NGRI analysed 34 large earthquakes across the globe, generating dynamic stresses of 1 kilopascal and more in the Arunachal Himalaya. NGRI has found that earthquakes and tremors are triggered even with a small amount of dynamic stress of 1 kilopascal when certain conditions meet in the region.
Bansal said that global studies have found that triggering could lead to even more significant earthquakes with magnitudes of more than 5.5 on Richter scale. When an earthquake occurs, the seismic waves travel all across the globe. Researchers said the study has the potential to identify vulnerability in north-east India and help understand the seismic hazard in the area.