The sea off some parts of Tuticorin district in south Tamil Nadu receded by more than 60 metre for the second day on Wednesday following the Indonesian earthquake.
Officials said there was no need to panic.
A report from Ramanathapuram said land to an extent of about 20 sq km was found 'exposed' around 21 islands in the Gulf of Mannar on Tuesday.
Gulf of Mannar Marine National Park's wildlife warden Naganathan said that normally, during low tide, the sea recedes by 4-5 metre, but on Tuesday even coral reef were visible in some areas in the region.
The receding of sea would continue for two more days and people need not panic, Head of the Geology Department of a college in Tuticorin Ramanujan said.