The Central Advisory Board of the Archaeological Survey of India (ASI) in January 2021 gave approval for the proposal to conduct a study of the Ram Setu. The study will be carried out by the Council for Scientific and Industrial Research (CSIR) and the National Institute of Oceanography (NIO). The study involves a three-year scientific project, which would begin by the end of March 2021.
Ram Setu is also known as Rama’s Bridge or Adam’s Bridge or Nala Setu. It is a 48-km-long chain of limestone shoals. It is located between Pamban Island (Rameswaram Island) of the South-Eastern coast of Tamil Nadu in India, and Mannar Island (Talaimannar) on the North-West coast of Sri Lanka.
The Geological Survey of India (GSI) in its study under ‘Project Rameswaram’ had indicated that the islands of Rameswaram in India and Talaimannar in Sri Lanka may have existed between 7,000 and 18,000 years ago. By the dating of corals (thermoluminescence dating), the GSI had stated that the Adam’s Bridge would have been formed between 500 and 600 years ago.
In the Ramayana, the existence of Ram Setu has been mentioned. However, till now, there is no scientific proof that it is a man-made bridge. It is believed that till the 15th century, the bridge was crossable on foot. The Rameswaram temple records seem to suggest that Ram Setu bridge was completely above the sea level till the year 1480. Due to natural calamities it got completely immersed in the shallow sea.
The Objectives of the Study
The scientific expedition will date the chain of corals and sediments forming the Ram Setu. In the three-year scientific project, the scientists would investigate whether Ram Setu was a man-made structure or not and establish the exact age of it, scientifically. It will also seek to find out whether there existed any submerged habitations around the Ram Setu. Once these details are collected, they would be verified and co-related with their references mentioned in the Ramayana.
Scientific techniques, including the carbon dating technique, would be used to determine the age of the sediments. They would also explore the material composition and outline the sub-surface structure. An attempt would also be made to excavate the remnants or artifacts, if any, from the site.
Initially, a survey will be carried out, making use of underwater photographs to check if there were any habitation remains immersed in the ocean. This will be done through a geophysical survey.
Once this phase is completed and studied, the scientists would then drill into the structure to gather samples to further perform laboratory-based studies.
There were a few mentions about the use of wooden slabs along the bridge in some of the scriptures, which would have been fossilised by now. The team of researchers, including archaeologists, would perform bathymetry (the study of ocean floors and seismic surveys). The study of the underwater expedition would be based on archaeological antiquities and radiometric and thermoluminescence dating for geological timescale.
The sea around the area of Rameswaram is mostly very shallow, as it is only 1 to 10 m deep with the depth rarely exceeding more than 90 m. The scientists would use local boats to ferry along the Setu. This is because large vessels or ships will not be able to sail in such shallow depths.
The NIO would operate with the help of two oceanographic vessels during this expedition:
- RV Sindhu Sadhana, India’s first-ever indigenously built research vessel was launched in 2014. It is equipped with laboratories for data collection, echo sounders, acoustic doppler, profiler, autonomous weather station, and air quality monitors. It has the ability to go up to and remain 80 m underwater.
- RV Sindhu Sankalp which has the ability to go up to and remain 56 m underwater.
The tests planned include:
- Side scan SONAR which would provide bathymetry; soundwave signals would be sent to the structure which would provide an outline of the physical structure of the Ram Setu.
Silo seismic survey which will test mild earthquake-like tremor shocks sent at shallow depths close to the structure, to penetrate into the structure; the reflected or refracted signals would then be captured by instruments that would provide sub-surface structure.
Other Underwater Explorations
Along the coast of Gujarat, a portion of Dwarka had been submerged under the water due to the rise in sea level. The NIO, which has been studying this site, has so far traced large amounts of stone anchors and artifacts, suggesting that the place was an ancient harbour. NIO had also initiated studies to trace the missing shore temples of Mahabalipuram in Tamil Nadu. Presently, several ship-wreckage studies, including the one off the Odisha coast, are in progress. Scientists have discovered a port located close to Goa and are considering it for a similar scientific study.
Significance of Underwater Explorations
India has a vast coastline of over 7,500 km. Oceans hold abundant bygone information regarding climate, evolutionary changes of the underwater fauna, coastal lives, habitations, settlements, and civilisations. Underwater research gives significant information with respect to climate studies.
Underwater exploration studies could lead to locating numerous ship wrecks and remains from the past. These remains could reveal a lot of information.