Ancient tsunami 'hit New York'

[emad]

A huge wave crashed into the New York City region 2,300 years ago, dumping sediment and shells across Long Island and New Jersey and casting wood debris far up the Hudson River.

The scenario, proposed by scientists, is undergoing further examination to verify radiocarbon dates and to rule out other causes of the upheaval.

Sedimentary deposits from more than 20 cores in New York and New Jersey indicate that some sort of violent force swept the Northeast coastal region in 300BC.

It may have been a large storm, but evidence is increasingly pointing to a rare Atlantic Ocean tsunami.

http://news.bbc.co.uk/1/hi/sci/tech/8028949.stm


Some years back at a geology lecture I heard a theory that a still non-defunct semi active caldera on the west coast of Ireland may have been responsible.

[aquart]

1. Yes, it could get messy.

[Dennis Donovan]

2. Rudy Giuliani's ancestor, Og Giuliani used the event as a politcal rallying cry...

:silly:

[L. Coyote]

3. The Megatsunami: Possible Modern Threat

The Megatsunami: Possible Modern Threat
Robert Roy Britt, Senior Science Writer - http://www.livescience.com/environment/041214_tsunami_mega.html


SAN FRANCISCO -- Volcanic landslides that generate huge and devastating tsunamis tend to occur during historically warmer times on Earth, a new study suggests. Scientists don't know exactly why, but since the global climate is warming as you read this, the apparent connection was tossed out this week as a reason for scientists to be concerned about the threat now.

Tsunamis are waves that race across the ocean without much fanfare but grow to frightening proportions when they reach land. The waves are deep, and while they may appear just a few inches or feet tall on the open ocean, they can soar to the height of a multi-story building as they are forced upward near the shore.

A tsunami can be generated by the sudden uplift of the seafloor in an earthquake, or by the paddle-like effect of a landslide crashing into the sea from, say, an island volcano. Yet while quake-generated tsunamis have been observed from their genesis to the disastrous end, scientists have never witnessed a significant open-ocean tsunami generated by a landslide.

Evidence exists at various locations around the world for megatsunamis, as scientists call the largest of these events. They seem to occur every 100,000 years or so .........

[Larkspur]

4. The Canary Islands may have been the ancient threat and is still one today

There's evidence of a landslide by the active volcano on the Canary Island and a few decades ago, a large rift appeared during the last major eruption. This rift could signal the beginning of another landslide that would create a mega tsunami in the Atlantic Ocean and affect the entire North American coast from Canada to Florida and possible the eastern Carribean islands.
Scientists Warn Of Massive Tidal Wave From Canary Island Volcano
Atlantic Ocean Tsunami Threat -- this link has a map of La Palma
Cumbre Viega Volcano: Potential Collapse and tsumami at La Palma, Canary Islands -- this link also has interesting maps

[Ghost Dog]

5. Yes indeed.

And of course such an event would also have dire consequences for coastal populations of the islands (100-metre level and higher) themselves and of neighboring northwest-African (tens of metres) and west-European Atlantic coasts, as you can see from the second set of images in the last link above.

Edit: In map at the second link above, it's most of the southwest corner of the island that will likely one day slip into the sea - where you see as it were 'stretchmarks' there... btw, it did occur to me to wonder what would happen if someone were to accurately target a few 'bunkerbusters' or similar just there.