HYDERABAD: Scientists from the Hyderabad-based National Geophysical Research Institute (NGRI) have played an important role in facilitating the ongoing rescue operations at Chamoli in Uttarakhand and are also studying the phenomenon that triggered the disaster, which might help in future to devise an early warning mechanism.
One of the most urgent tasks in the aftermath of the disaster at Chamoli, was to rescue the survivors, including those who might have got stuck inside the tunnel of the NTPC Hydel Power Plant project in Tapovan.
NGRI Director Dr VM Tiwari, told Express, “The first priority for the event was rescue operation. Therefore, within 48 hours, CSIR-NGRI undertook the heliborne geophysical 3D mapping in the Tapovan project area to identify the extent of slush penetration in the tunnels. A report has been submitted to authorities concerned. This information helped the authorities to plan the rescue and rehabilitation operations.”
Dr Tiwari added, “Further, using geophysical instruments, we are trying to understand the rock slide/snow avalanche phenomena which shall have a direct application for the design of early warning system.” The 3D mapping report by NGRI gave a clear idea of the condition inside the tunnel on the survey day- in which locations air bubbles are located and where the tunnel is completely sealed off with slush/water.
What triggered the disaster?
Dr Tiwari said, “Based on satellite image analysis, and other observations it appears that bedrock landslide at a higher elevation on the morning of February 7, 2021. The rock mass of landslide has fallen on the frozen stream bed. That triggered the mass movement of partially saturated debris flow (sediment, ice, and melted ice/snow) and thus water flow was less than flash flood observed during 2013.”
He added that investigations were underway whether this rock slide was triggered by a natural phenomenon such as heavy snowfall or seepage of water in the fractured zone from glacier melts over the time etc.
Role of global warming in the calamity?
Dr Tiwari said, “The role of global warming needs to be explored keeping in mind long term events. There is no clear answer as of now. But the region is vulnerable to the recurrent slope failure due to highly deformed rocks in the earthquake prone region which is also glaciated.”