Threat to America demonstrated in Indonesia

[yankeedoodle]

Back in 2004, after the Boxing Day (December 26, 2004) tsunami killed hundreds of thousands of people, there was a brief period of media discussion about the possibility that a volcano in the Canary Islands could created an enormous landslide that would trigger a mega-tsunami that would propel the Atlantic Ocean to devastate America.

'Worst-case scenario'
Back in 1999, scientists at University College London published a paper about a volcano on the island of La Palma. They predicted that, if it erupted, the volcano could cause a landslide in which a massive chunk of land fell into the ocean.

They then proposed that a landslide this big would generate a mighty tsunami big enough to cross the Atlantic, devastating the Caribbean and the eastern seaboard of the US.
   
If you break [a brick] up into 10 pieces and drop them in one by one you're going to get 10 much smaller splashes 
Russell Wynn, Southampton Oceanography Centre
With talk of a possible wall of water 50m high, their predictions were jumped on by the world's media.

But researchers taking part in a three-week research cruise aboard Southampton Oceanography Centre's research ship, the RRS Charles Darwin, say the threat is far lower than previous warnings would suggest.

Tidal wave threat 'over-hyped'
http://news.bbc.co.uk/2/hi/3963563.stm

At the time, in the above article, In maybe typical BBC fashion, this threat was downplayed.  (Obviously, at the time, it didn't occur to them that the Russians could do it.)

Now, almost 14 years later, on December 22, 2018, a island volcano DID create a landslide that triggered a tsunami, and, now, the BBC is taking the threat very seriously, as described in the article below.

Nobody had any clue. There was certainly no warning. It's part of the picture that now suggests a sudden failure in the west-southwest flank of the Anak Krakatau volcano was a significant cause of Saturday's devastating tsunami in the Sunda Strait.

Of course everyone in the region will have been aware of Anak Krakatau, the volcano that emerged in the sea channel just less than 100 years ago. But its rumblings and eruptions have been described by local experts as relatively low-scale and semi-continuous.

In other words, it's been part of the background.

And yet it is well known that volcanoes have the capacity to generate big waves. The mechanism as ever is the displacement of a large volume of water.

[...]

Landslide- or rockfall-driven tsunamis can be very big indeed. In the geological record, they have been responsible for gargantuan events.

Just recently in Greenland in 2017, a 100m (330ft) wave was produced by a rockslide entering a fjord in the west of the country; and there is still some suspicion that September's damaging tsunami that affected Sulawesi Island in Indonesia was, in part at least, strengthened by the mass movement of sediment, either entering the water from shore or slipping down underwater slopes in Palu Bay.



Indonesia tsunami: How a volcano can be the trigger
https://www.bbc.com/news/science-environment-46666633