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Lutz Möller
Installation of a Tsunami
Early Warning System in
the Indian Ocean
A Joint Effort by Germany and Indonesia
The tragic loss of human life
caused by the December 2004
tsunami has proven mankind’s
high degree of vulnerability in the
face of natural disasters. Aware of
the fact that such disasters cannot
be prevented entirely, Germany
has committed itself to making a
contribution to mitigating the effects
of future tsunamis in the Indian
Ocean. In collaboration with
Indonesia, and as a contribution
to the regional tsunami early
warning system under the umbrella
of UNESCO’s Intergovernmental
Oceanographic Commission
(IOC), Germany will implement
an early warning system for Indonesia.
Thus, it will demonstrate
that cutting-edge technology plays
a key role in effective disaster
mitigation, and can diminish the
tragedy of disasters such as the
December 2004 tsunami.
When the sea floor abruptly rises or
falls, or in case of coastal or undersea
landslides, large amounts of sea
water are displaced. The consequence
of such an event is the
spread of the disturbance across the
ocean – not on the surface, but within
the entire volume of the ocean.
This disturbance is called a tsunami.
The physics of a tsunami is rather
simple, but the phenomenon is highly
counter-intuitive. The Japanese
word “Tsunami” means “harbour
wave”, a wave which suddenly
seems to appear out of nowhere,
close to a coastline. Tsunamis are
gravity-triggered waves of energy instead
of water: the individual water
molecules are in fact displaced only
by tiny distances. Tsunamis in the
open sea have a comparatively small
height – less than a meter – and an
enormous speed – more than 500
km per hour. Close to the coast, the
water piles up and forms a slow but
very steep wave, which looks rather
like a fast and infinitely onrushing
tide. The actual damage is caused by
the enormous mass of water behind
the wave front, as the sea keeps
flooding powerfully into the coastal
area.
Most people were entirely unprepared
for this apparently unusual
phenomenon in December 2004 – on
a day which now stands for the most
tragic loss of human life caused by a
natural disaster in the global collective
memory. On December 26th
2004 the sea floor 150 km west off
Sumatra slipped vertically by more
than 15 meters on the border of two
tectonic plates. This incredibly strong
earthquake, with a magnitude of 9.3,
which was followed over ten minutes
by an immense rupture process
over a length of about 1,200 km,
was the second strongest in recorded
history. However, it was the consequences
which made this earthquake
truly notorious – the Indian
Ocean tsunami, a disaster resulting
in a death toll of more than 250,000.
Tsunamis are not predictable and
they cannot be prevented. However,
modern technology allows for
tsunamis to be detected very quick-
1972
World Heritage
Convention. The
17th General Conference
(17th October
to 21st November)
passes the Convention
Concerning the Protection
of the World Cultural and
Natural Heritage, which
comes into force in 1975.
Today, 180 states have ratified
the Convention.
Admission of East Germany.
On the 21st November the
General Conference, extended
for an extra day, accepts the
third application for admission
submitted by the German
Democratic Republic as the
130th member state. UNESCO
is the first UN agency to
which the GDR is admitted.
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