Mega Waves

29 Feb 2020

Sent in by William. At https://eos.org/articles/submarine-canyons- breed-megawaves-in-japan/ ... submarine canyons on the continental shelf system offshore of Toyama Bay in Japan seem to be involved in the huge winter waves that appear out of nowhere - up to 32 feet high. Wave after wave can batter the shoreline, all day long. The waves have been documented for centuries but scientists have been flummoxed as to how they form. The shape of the bay's peninsular allows only ocean swells from the north and northeast to travel inland ...

   ... they travel over submarine canyons (or former river channels) lining the bay's coastline (valleys beneath the sea) with cascading walls and gullies that stretch through the continental shelf system down to deep ocean. These canyons focus the swells - interacting with them as they come ashore. It has been given a name - coherent interference (see https://en.wikipedia.org/wiki/Coherence_(physics) ... ). The same phenomenon occurs elsewhere around the world - in California for example, and offshore Portugal. We saw, a few weeeks ago, that within the Bermuda Triangle there were deep gouges on the sea floor in the Caribbean south and east of Florida, and again, a deep canyon rift running up the middle of the North Sea. Is there a connection?