Jakarta Globe – AFP, December 14, 2013
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| Scientists said they have discovered a cave Lhonga Leupung, Aceh, that provides a ‘stunning’ record of Indian Ocean tsunamis over thousands of years. (AFP Photo/C.M. Rubin) |
Scientists
said Friday they have discovered a cave on the Indonesian island of Sumatra
that provides a “stunning” record of Indian Ocean tsunamis over thousands of
years.
They say
layers of tsunami-borne sediments found in the cave in northwest Sumatra
suggest the biggest destructive waves do not occur at set intervals — meaning
communities in the area should be prepared at all times for a tsunami.
“It’s
something that communities need to know,” research team leader Charles Rubin
told AFP, adding that the team wanted to “promote safety of coastal
communities”.
Professor
Rubin and other researchers from a Singapore institute were working with
scientists from an Indonesian university when they discovered the cave, south
of Banda Aceh, the capital of Aceh province.
A
quake-triggered tsunami devastated Aceh and areas across the Indian Ocean in
2004, leaving some 170,000 people dead in the province alone.
Inside the
cave the researchers found layers of sandy sediment, which had been washed in
by tsunamis thousands of years previously, Rubin said.
The layers,
which contained small fossils from the seabed, were well-preserved and
separated by droppings deposited by bats in the cave, he added.
“This is a
beautiful, stunning record of tsunamis that you just don’t have very often,”
Rubin said.
Only huge
tsunamis and storm surges can get into the cave, which has a raised entrance —
and afterwards the sediment is protected inside from erosion by wind or water.
Rubin said
the scientists dated the layers and believe they show that between 2,800 and
3,300 years ago, some four to five tsunamis battered the area.
Before the
2004 tsunami, it had been hundreds of years since such a huge destructive wave
had hit Aceh, the scientist said.
But he said
the new discovery suggests that tsunamis are not evenly spaced through time,
which should provide food for thought for those involved in policy and planning
in the region.
“These
don’t happen like clockwork, they have variations in time and variations in
size,” he said.
Rubin works
at the Earth Observatory of Singapore, an institute that forms part of Nanyang
Technological University.
Scientists
from the institute were working with researchers from Syiah Kuala University in
Banda Aceh.
Agence France-Presse
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