Speaking to IANS, outgoing Director of the National Institute of Oceanography S.W.A. Naqvi also said that tsunamis were not new to the western Indian coastline, the latest being in 1945, which hit the coast of Gujarat and whose effects were felt in Mumbai as well as Goa.
"I think we need to be careful, that if this is a tsunami-prone area and we have a very recent evidence that it happened around 70 years ago, planners must take that into account," Naqvi said.
The tsunami phenomenon is normally associated with the country's eastern coastline and the extreme southern reaches of Kerala.
Naqvi, however, said that two major tsunamis were recorded along he western coast as well. While one such wave measuring as high as 10 metres rocked the Gujarat coast in November 1945, the other such tsunami was recorded around five centuries ago, even affecting a Portuguese fleet, sailing near the coastline.
"I think it also happened in 1520s, shortly after the Portuguese came here. Their fleet was also affected," he said.
The tsunamis, he said, occur due to seismic activity in the Makran region off Gujarat, which is a boundary between two plates and is tectonically active area.
"There was a major earthquake of 8.1 Richter scale (in 1945). That tsunami hit Mumbai and our feeling is it may have come to Goa too," he said.
The third and possibly one of the earliest recorded tsunamis, Naqvi said, could have occurred 3,500 years ago at Dholavira, once a port and the biggest Harappan site in India.
"At Dholavira 5,000 years back, they had a fair idea that this was a tsunami prone area, but because economically it was a very strategic area, they built the city and port. But they also built an 18-metre (thick) wall to protect them from the tsunami," Naqvi said. The port town flourished for around 1,500 years before a tsunami destroyed it, the scientist said.
"Our hypothesis is that it was built as a protective measure against marine disasters, tsunamis and storm surges because it was a major port at that time," he added.
