Scientists have identified a 2,291 sq km area in Uttarakhand’s Chamoli district as the “most seismically active zone in Uttarakhand Himalayas” after they found that it had the highest density of earthquakes and landslides over the study period of eight years. The flash floods in February that killed 200 people in Chamoli had also occurred in an area within this zone.
Researchers at the Dehradun-based Wadia Institute of Himalayan Geology (WIHG) studied the Main Central Thrust (MCT) zone, a 2,200 km-long geological fault along the Himalayan belt which demarcates the lesser Himalayas from the higher Himalayas. The zone has been touted as the “geographically weakest” part of the Himalayas since all earthquake-related activity in the Himalayas have happened in and around a 10km periphery of MCT, according to scientists.
For the study, researchers looked at the part of MCT which fell in Uttarakhand, a total area of 19,000 sq km. The study, published in Current Science journal, analysed data of earthquakes and landslides in the region between July 2007 and October 2015.
Data from seismographs was collected to study earthquakes while landslide data was procured by high resolution satellite images as well as images on the Google Earth platform.