Underwater Krishna-Godavari basin landslide can trigger tsunami: Scientists

PANAJI: A recently discovered landslide in Krishna-Godavari basin, reaching between 950m and 1.1km below the ocean surface, could pose a serious risk to underwater structures, Goa-based National Institute of Oceanography (NIO) said. “The huge landslide can displace a large amount of water and bottom sediments, potentially causing a tsunami,” NIO director Sunil Kumar Singh told TOI.
NIO scientists said the landslide in Bay of Bengal could have occurred anytime between 2009 and 2015. “It poses a significant risk to underwater communication cables and oil rigs, as well as to people living on the coast,” NIO said.
The scientists believe that when the landslide occurred, it caused a massive section of the seabed to collapse, moving around 11 cubic km of sediments – enough to fill about 44 lakh Olympic-size swimming pools. At some places, the landslide deposits are up to 60m thick, NIO said. This giant underwater landslide, known as a mass transport deposit (MTD), has created a large fan-shaped deposit on the ocean floor, they said. The area the MTD covers is about 70sqkm – roughly the size of 10,000 football fields.
The landslide was uncovered using special equipment that tracks changes in the ocean floor over time and was one of the largest underwater slope failures ever found in this part of the ocean, NIO said. The scientists believe several factors might have caused the landslide. One important factor could be Cyclone Helen, a category-1 storm that hit the region in Nov 2013.
The cyclone’s powerful winds and strong waves may have triggered the collapse. Other possible causes include extreme flooding events in 2010 and 2013, and a powerful 6 magnitude earthquake that shook Bay of Bengal in May 2014. They said even events like cyclones, heavy rain, and earthquakes that seem small on their own can trigger massive underwater landslides, especially if the ocean floor sediments are already weakened.
Scientists are now urging more research and monitoring of areas like KG basin to better understand and predict underwater hazards.