Can seismic activities change the course of rivers? Well, a study reveals that a major earthquake that occurred 2,500 years ago caused one of the biggest rivers on the planet to change its course abruptly. That river was none other than the Ganges.
This breakthrough discovery about changing courses of rivers is known as avulsions in scientific terminology. Rivers have always been changing their courses, but it was never confirmed that earthquakes could be the driving force behind them. Certainly, no study has ever linked seismic activity with the Ganges’ course before, which makes this study one-of-a-kind.
Today the Ganges flows for over 2,575 kilometers (1,600 miles) from the Himalayas down to the Bay of Bengal. It forms the world’s second-largest river system as it teams up with other rivers.
It is hard to collect that such a massive water body system can change its course due to an earthquake. But course changes take decades and a lifetime. It is because sediments washed from upstream can change the lay of the land, raising the riverbed until the water finds a path of less resistance by flowing in a slightly different direction.
Earthquake changes the course of the Ganges
Avulsions need not require time of decades or even years to make a change. As per the new study, earthquakes can lead to changes in rivers that happen almost instantaneously.
Looking at satellite imagery, the team discovered what appeared to be a former main channel for the Ganges running parallel to the river as it runs today for around 100 kilometres (62 miles).
They were exploring the area in 2018 when they spotted something interesting along the retired river’s flank- sand volcanoes. Also known as seismites, they’re characterised by strips of sand emerging vertically through horizontal layers of mud and are a known side effect of earthquakes.
They also found seismites across a large expanse of land and all of them seemed to have similar patterns, indicating they were created at the same time.
The chemical analysis of the seismites revealed they date back 2,500 years, when what the researchers suggest was a magnitude 7 or 8 earthquake reshaped the landscape.
The source of the Ganges-shifting earthquake could have originated from a subduction zone to the south and east where part of the oceanic crust is working its way underneath Bangladesh, Myanmar, and northeastern India.
Also, the large splay faults at the base of the Himalayas may have been the driving force, which is a concerning possibility as research suggests these zones could be due to another earthquake similar in magnitude to that which changed the course of the Ganges.
(With inputs from agencies)
Can seismic activities change the course of rivers? Well, a study reveals that a major earthquake that occurred 2,500 years ago caused one of the biggest rivers on the planet to change its course abruptly. That river was none other than the Ganges.
This breakthrough discovery about changing courses of rivers is known as avulsions in scientific terminology. Rivers have always been changing their courses, but it was never confirmed that earthquakes could be the driving force behind them. Certainly, no study has ever linked seismic activity with the Ganges’ course before, which makes this study one-of-a-kind.
Today the Ganges flows for over 2,575 kilometers (1,600 miles) from the Himalayas down to the Bay of Bengal. It forms the world’s second-largest river system as it teams up with other rivers.
It is hard to collect that such a massive water body system can change its course due to an earthquake. But course changes take decades and a lifetime. It is because sediments washed from upstream can change the lay of the land, raising the riverbed until the water finds a path of less resistance by flowing in a slightly different direction.
Earthquake changes the course of the Ganges
Avulsions need not require time of decades or even years to make a change. As per the new study, earthquakes can lead to changes in rivers that happen almost instantaneously.
Looking at satellite imagery, the team discovered what appeared to be a former main channel for the Ganges running parallel to the river as it runs today for around 100 kilometres (62 miles).
They were exploring the area in 2018 when they spotted something interesting along the retired river’s flank- sand volcanoes. Also known as seismites, they’re characterised by strips of sand emerging vertically through horizontal layers of mud and are a known side effect of earthquakes.
They also found seismites across a large expanse of land and all of them seemed to have similar patterns, indicating they were created at the same time.
The chemical analysis of the seismites revealed they date back 2,500 years, when what the researchers suggest was a magnitude 7 or 8 earthquake reshaped the landscape.
The source of the Ganges-shifting earthquake could have originated from a subduction zone to the south and east where part of the oceanic crust is working its way underneath Bangladesh, Myanmar, and northeastern India.
Also, the large splay faults at the base of the Himalayas may have been the driving force, which is a concerning possibility as research suggests these zones could be due to another earthquake similar in magnitude to that which changed the course of the Ganges.
(With inputs from agencies)
### Earthquake Alters Ganges Path
Earthquake Alters Ganges River Course: Study
A groundbreaking study has revealed that a major earthquake 2,500 years ago caused the Ganges River, one of the world’s largest, to change its course abruptly. This phenomenon, known as avulsion, had never been linked to seismic activity affecting the Ganges before.
The Ganges, spanning over 2,575 kilometers from the Himalayas to the Bay of Bengal, is part of the world’s second-largest river system. While river courses can change over decades due to sediment deposition, this study indicates that earthquakes can cause almost instantaneous shifts.
Researchers discovered what seemed to be a former main channel of the Ganges running parallel to its current path, along with sand volcanoes, or seismites, which are indicative of past earthquakes. Chemical analysis dated these formations back 2,500 years, suggesting an earthquake of magnitude 7 or 8 as the cause.
The likely sources of the earthquake include a subduction zone around Bangladesh, Myanmar, and northeastern India, or large splay faults at the base of the Himalayas. These findings raise concerns about the potential for similar seismic events in the future.
Reported by Riya Teotia, Senior Sub-Editor at WION.