Can a massive earthquake like the one that occurred 2500 years ago occur again? The Ganga river had changed its main route
About 2500 years ago, a powerful earthquake struck the earth. According to a new study published in the journal Nature Communications, a powerful earthquake struck about 2,500 years ago. Its magnitude was between 7 and 8. It had the ability to suddenly change the course of the Ganges River and dramatically changed the main path of the river. Which is now in earthquake-prone Bangladesh. Although this event was not recorded in historical documents, recently researchers have found evidence that this event took place. This study helps in understanding seismic history.
Researchers had seen seismites, shapes formed as a result of an earthquake in Bangladesh, while exploring the area of the main route of the Ganges River in 2018. According to them, many such shapes were formed at the same time. Chemical analysis of the sand and mud here showed that an earthquake of about 7-8 magnitude occurred in this area about 2,500 years ago.
Researchers say that such a powerful earthquake could have come from two possible sources. The first is a subduction zone in the south and east, i.e. the edge of one plate of the Earth’s crust moves diagonally and downward into the mantle (shell) beneath the other plate. Here a huge plate of oceanic crust is pushing itself under Bangladesh, Myanmar and northeastern India. The second possibility is that the seismic shock came from the presence of large cracks in the foothills of the Himalayas in the north. Because these cracks are formed by the slow collision of the Indian subcontinent with the rest of Asia. Because of this, the Himalayas are becoming higher over time. A study conducted in 2016, led by Michael Steckler, a geophysicist at the Lamont-Doherty Earth Observatory of Columbia Climate School, US, and co-author of the study, showed that these areas are building up tension and can produce earthquakes equivalent to the earthquake that occurred 2,500 years ago. The study estimates that if this had happened in modern times, about 140 million people would have been affected.
Scientists around the world have observed changes in the course of many rivers, called ‘eruptions’. Some of these were caused by earthquakes. Steckler said that rivers can take years or decades to change their course, but an earthquake can cause an erasure almost immediately. He said, I don’t think we have ever seen such a big earthquake anywhere. This earthquake could easily submerge any person or thing in the wrong place at the wrong time. The Ganges river, which originates from the Himalayas, eventually joins other major rivers including the Brahmaputra and the Meghna and merges into the Bay of Bengal. These rivers form the world’s second largest river system after the Amazon. However, like other rivers flowing through major deltas, the Ganges also changes its course regularly.
According to lead author Elizabeth L. Chamberlain, assistant professor at Wageningen University in the Netherlands, this study is the first solid example of silting in a delta, especially for a large river like the Ganges. Using satellite images, the research team discovered the former main course of the Ganges River about 100 kilometers south of Dhaka, the capital of Bangladesh. It is a low-lying area about 1.5 kilometers wide, which was found intermittently for about 100 kilometers parallel to the current river course. He said that due to being filled with silt, it often floods.
