A day after a new tsunami alert in the Andamans, scientists said the aftermath of the earthquake that caused the 2004 disaster is still pushing around land mass in the region like skidding of a car after the sudden use of a brake.
The capital Port Blair, which was pushed more than three metres towards Chennai on the day of the tsunami, has slowly inched a 10th of that distance more over the past three years and the city and its island have partially risen after sinking a little less than a metre, according to a just-completed study.
The tsunami destroyed vast parts of the Andaman and Nicobar archipelago, a sprawling network of islands in the Indian Ocean. Almost 7,500 people died and large swathes of beaches, coconut plantations and coral reef were destroyed.
The study, conducted by the Society for Andaman and Nicobar Ecology (SANE) and the Bangalore-based Indian Institute of Astrophysics, studied Global Positioning System data from a total of 40 sites in the Andamans over three years.
It found that the island on which Port Blair is located had shifted 310 centimetres in the West-Southwest direction on December 26, 2004; it has moved a further 32 centimetres towards the Indian mainland since. There was up-and-down movement as well the land slumped 86 centimetres during the earthquake, but had since risen more than a quarter about 26 centimetres. The western part of the island has tilted up; the eastern has gone down.
“It is like a school see-saw,” said John Paul, a quake expert who lead the project. “All this can possibly help us understand how often destructive earthquakes occur along the fault in the region,” he told HT. “Earlier we didn’t have such GPS data.”
Scientific studies of Andaman and Nicobar have been discouraged in the past due to security concerns, and the situation has only marginally improved after the tsunami, when scientists rushed to measure the losses to the region’s rare biodiversity and earthquake risks.
Experts say concerns over scientific data collection in the Andamans are often misplaced.