The cave holds a record of tsunami in history

A cave in Indonesia's northwestern Sumatra Island keeps deposited sand and sediment from bat manure thousands of years ago to help scientists determine the frequency of tsunamis in the Indian Ocean as a disaster on the day. December 26, 2004.

Scientists at the Singapore Earth Observatory at Nanyang Technological University said evidence of sediment from the tsunami brought into the cave near Banda Aceh city is easy to see under the layers of bat dung in the cave.

This cave is located far from the place where the waves often hit the shore at high tide about 100 meters toward the mainland, so the sea does not reach the cave mouth unless there is a big storm and tsunami. Therefore, the tsunami evidence from 3,000 years to 7,500 years remains intact.

Sediments from bat dung and sand in the cave allow scientists to identify the tsunami in history - (BBC Photo)

Surveys continue, but the team thinks they can see the sediments of 7 to 10 tsunamis in history. Scientists have dug holes through the layer of bat and sand, together to learn about the history of the cave.

They may be able to confirm the sediment of the tsunami thanks to the detection of sediments of microscopic organisms on the seabed like foraminifera . Only very strong waves can bring them up and put them into the cave.

The dating of sediments thanks to the analysis of radioactive carbon on evidence found in this cave allows for confirmation of tsunamis in history.