Re:New nuclear plant at Sizewell set for green light
by manfredo on Tuesday November 03, 2020 @09:24PM
(#24986101)
Yes, caused by an earthquake 500 times more powerful than the magnitude 4.5 you had previously stated:
> An offshore earthquake of magnitude 4.5 or above could cause submarine avalanches and create dangerous tsunamis with waves higher than 26 feet
Turbidity currents occur on the regular without earthquakes and rarely result in substantial waves. They have been observed to happen due to earthquakes, but this is a rare event. The Grand Banks quake is the only known earthquake to have done this, and as you pointed out it was an earthquake with a much larger magnitude.
In the grand scheme of things, turbidity events don't significantly impact the overall risk of tsunamis. The tsunami risk overwhelmingly comes from the earthquakes themselves, not the turbidity events they may trigger.
"A 7.2-magnitude earthquake off the southern coast of Newfoundland in 1929 caused a large underwater landslide, creating a large wave that rushed ashore and killed 28 people on the island, ten Brink said. The waves were up to 26 feet high until some reached narrow inlets, where they grew to 43 feet (13 m), he said."