En español / In Spanish
Scattered across the world’s oceans are a handful of rare geological
time-bombs. Once unleashed they create an extraordinary phenomenon, a
gigantic tidal wave, far bigger than any normal tsunami, able to cross
oceans and ravage countries on the other side of the world. Only recently
have scientists realised the next episode is likely to begin at the Canary
Islands, off North Africa, where a wall of water will one day be created
which will race across the entire Atlantic ocean at the speed of a jet
airliner to devastate the east coast of the United States. America will
have been struck by a mega-tsunami.
Back in 1953 two geologists travelled to a remote bay in Alaska looking for
oil. They gradually realised that in the past the bay had been struck by
huge waves, and wondered what could have possibly caused them. Five years
later, they got their answer. In 1958 there was a landslide, in which a
towering cliff collapsed into the bay, creating a wave half a kilometre
high, higher than any skyscraper on Earth. The true destructive potential
of landslide-generated tsunami, which scientists named "Mega-tsunami",
suddenly began to be appreciated. If a modest-sized landslide in Alaska
could create a wave of this size, what havoc could a really huge landslide
cause?
Scientists now realise that the greatest danger comes from large volcanic
islands, which are particularly prone to these massive landslides.
Geologists began to look for evidence of past landslides on the sea bed,
and what they saw astonished them. The sea floor around Hawaii, for
instance, was covered with the remains of millions of years’ worth of
ancient landslides, colossal in size.
But huge landslides and the mega-tsunami that they cause are extremely rare
- the last one happened 4,000 years ago on the island of Réunion. The
growing concern is that the ideal conditions for just such a landslide -
and consequent mega-tsunami - now exist on the island of La Palma in the
Canaries.
MORE ON...
http://www.bbc.co.uk/science/horizon/2000/mega_tsunami.shtml
