Dholavira site has first evidence of tsunami


National Institute of Oceanography (NIO) team has unearthed the world’s oldest known site to have been hit and submerged by a tsunami. Research provides an evidence of burial of parts of Dholavira, the ancient metropolitan port town of the Harappan period in Gujarat.
Addressing the media alongwith the team of researchers working on the project, NIO Director Dr SWA Naqvi stated that the research indicates that the site at Dholavira is the oldest known site in the world to have been hit by a tsunami.
He said, “The soil samples have been found to contain fossils of foraminifera, microscopic organisms that build calcareous shells and live only in seawater. This presence of shells of marine organisms in the soil strongly suggests an episodic deposition of marine sediments in the area. This deposition could have occurred as a result of a massive tsunami.”
Naqvi said that Dholavira was the largest port town of the Harappans and is the second largest Harappan site located within the present borders of India. He said that the well-planned urban settlement was a major port for about 1,500 years from about 5000 to 3450 years before present.
Detailing the present research, the NIO Director said in July this year archaeological excavations showed that the township comprised of three parts – the castle, the middle town and the lower town.
“A unique feature of Dholavira is the presence of a 14-18 metre thick wall, apparently built as a protective measure. Intriguingly, walls of such thickness are not found even in historic times when the conflicts have been more common and the weapons had become increasingly more destructive. Therefore, the real purpose of the Dholavira wall has been a topic of considerable debate,” he said.
Naqvi said that the team led by Dr Rajiv Nigam, retired senior scientist of NIO, has proposed that the thick wall was built to protect the town from extreme oceanic events such as storm surges and tsunamis. Nigam said that the team had first visited the site in May 2014. He said that the team comprising of palaeoclimatologists, archaeologists and geophysicists surveyed the unexcavated area using ground penetrating radar (GPR) and collected soil samples.
“The GPR records show 2.5-3.5 metre thick homogenous soil layer below the surface, which suggests its episodic deposition, possible due to an extreme event. The exact timing of the sediments deposited in Dholavira is yet to be established. However, the results clearly indicate that massive tsunamis are not uncommon in the region,” he added.
He stated that the thick wall in Dholavira shows that the Harappans were not only aware of the potential threats from tsunamis, but they were also pioneers in coastal disaster management. “Most importantly, results of this study open the possibility that Dholavira, at least in part, could have been destroyed by such a tsunami,” he said.