British survey ship releases color image of earthquake seabed
Jack Linthicum
off the coast of Java in Indonesia is in the original cite.
http://www.channelnewsasia.com/stories/afp_asiapacific/view/131779/1/.html
Time is GMT + 8 hours
Posted: 10 February 2005 0853 hrs
British navy releases first images of Indian Ocean earthquake seabed
LONDON : A British Navy survey ship released the first images of the
seabed at the epicenter of last year's killer earthquake and tsunami
that reveal the massive canyons and ridges left by the collision of two
of the earth's plates.
The Royal Navy's HMS Scott has been taking underwater sonar readings
off the Indonesian island of Sumatra to try to find out how the
December 26 earthquake unfolded and then produced the giant waves that
have killed nearly 300,000 people in 11 countries.
The ship's officers presented the readings in the form of colored
digital mapping at the United Kingdom Hydrographic Office in Taunton,
Somerset, southwest England, indicating a large landslide some 100
metres high (328 feet) by two kilometres (1.2 miles) in length.
HMS Scott's Commanding Officer Steve Malcolm said initial assessments
by scientists indicate two of the earth's tectonic plates clashed
together, causing a ridge on the seabed which forced sea water to
travel upwards to form the devastating tsunami.
It must have occurred "like the rumpling up of a carpet," he said.
He said he hoped the survey would give a warning as to when this could
happen again "with the aim of removing the likelihood of such a
terrible loss of life".
HMS Scott's survey will provide the "base map" for future extensive
research into the process of how earthquakes work and how they produce
tsunamis.
Data will help produce charts to build a picture of what happened on
December 26 and what might happen next.
The commander said it was hoped the Indonesian government would permit
the release of as much information as possible to the wider local
community "to give warning to prevent such a tragedy happening again".
He said the survey and its images, though unable to give exact
predictions of when earthquakes will occur, could indicate a level of
risk.
The depth of the water in the area of the epicenter varies between 200
and 5,000 metres (670 and 16,700 feet), all of which is within the HMS
Scott's capability, scientists say.
The epicenter of the quake, which measured a massive 9.0 on the Richter
scale, lies within the Indonesian Exclusive Economic Zone.
The survey will fall under the definition of Marine Scientific Research
under the United Nations Convention on Law of the Sea.
HMS Scott sailed from Plymouth's Devonport Naval Base in November last
year to undertake a program of military-based data gathering in the
North Atlantic, Arabian Sea and Indian Ocean.
Scientists from Southampton Oceanography Centre and the British
Geological Survey have been working with the crew on the Scott since
January 26.
The images show bands of color representing different seabed depths due
to ridges and canyons in the seabed structure. Those in blue are some
4,300 metres deep (canyons) while those in red are shallower at around
1,000 metres deep (ridges).
The naval staff said they believed that after the collision of the
plates, high ridges in the structure of the seabed crumbled to form a
"canyon".
The images show the "canyon" created from the landslide movement in
blue. Commander Malcolm described this movement as like "scree sliding
down the side of a quarry".
Royal Navy Captain Ian Turner told the conference: "I believe from a
scientific perspective the images from the seabed of Sumatra are no
less exciting or significant than the images we saw recently beamed
back from space from the surface of the planet Triton."
The earthquake's epicentre is shown on the images with a small yellow
dot and the centre of movement of the plates is shown with a red dot.
- AFP