Earthquake 2,500 years ago abruptly changed Ganga river’s course
- Based on geological measures in the Ganga river area, researchers found the Ganga had abruptly changed its course or avulsed about 2,500 years ago, leaving behind the palaeochannel.
- Paleochannel is a well-preserved mud and sand archive of the river’s ancient course about 45 km to the south of the modern Ganga river.
- Today, the area is used to cultivate rice.
Study findings
- During their fieldwork, the team also chanced upon two large sand dikes a kilometre to the east of the palaeochannel.
- These dikes are formed when earthquakes disturb the river bed and cause sediments to flow as if they were liquid.
- Scientists call this process liquefaction.
- The study’s findings call for urgent forecasting of major earthquakes that can cause avulsion of rivers like the Ganges
Future hazards
- This discovery that large earthquakes can potentially trigger major river avulsions suggests that the impact of large earthquakes can be even more devastating than previously thought
- Avulsions have caused some of the deadliest floods in human history, and the cascading impacts of earthquakes and flooding can be severe for heavily populated regions like the Ganges-Meghna-Brahmaputra delta.
- The risk is exacerbated by human activities and climate change,
- Future research should focus efforts to find out how often such quake-driven avulsions have happened and how such major earthquakes can be forecast.