Hong Kong tsunami chance 10 percent in century for 2 metre w

Hong Kong and the neighbouring territory of Macau face a roughly 10 percent risk of being hit by a devastating tsunami in the next hundred years, scientists say.

The danger stems from where the bed of the South China Sea ducks under the Manila Trench, a boundary in the notoriously seismic Philippine Sea plate of the Earth’s crust.

An earthquake on the Manila Trench could cause giant waves that would radiate across the shallow sea, placing major cities in harm’s way, according to computer simulations by scientists in China, the United States and Japan.

According to their calculations, a 7.5-magnitude quake occurring on parts of the Trench southwest of the Philippines would unleash a wave of over two metres, which would endanger a 400km swathe of the coast of Guangdong province, from Macau and Hong Kong in the south to Shantou in the north.

The risk of this happening over the next century is 10,12 percent for Hong Kong and Macau and 13,34 percent for Shantou, scientists believe.
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Since AD 171, 11 tsunamis have hit the Chinese mainland coast and Taiwan, the biggest of which was a wave 7,5m high that struck Keelong, Taiwan, on December 18, 1867.

Hong Kong has not been seriously affected by any tsunami in recorded history, with the Philippines Islands and Taiwan acting as an almost complete breakwater for such tsunamis in the Pacific. Diffracted sea waves are much weaker and therefore the energy that arrives in Hong Kong has been fairly small.