Why in news
In June 2024, researchers reported that an earthquake of magnitude 7 to 8 was responsible for shifting the Ganga more than two millennia ago
Researchers found two large sand dikes, which were the first proof that earthquakes can move rivers.
Dating Technique Used
Optically Stimulated Luminescence (OSL) Dating: This technique estimates how long a mineral grain, like quartz, has been buried by measuring the natural radiation it has absorbed over time.
The amount of radiation stored in the grains reveals how long they’ve been buried.
Paleochannel
A paleochannel is an ancient, well-preserved riverbed or channel that shows the historical course of a river.
It consists of layers of mud and sand that were deposited by the river when it flowed through that area.
Impact of the Earthquake
Formation of Sand Dikes:
Earthquakes can cause sediments in riverbeds to behave like a liquid, forming sand dikes.
This process, called liquefaction, was used to link ancient earthquakes with river changes.
River Avulsion:
Shifting the course of the River, leading to the formation of the paleochannel.
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