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. Last Updated: 07/27/2016

Scientist: Man Underrating Tsunamis

WOLLONGONG, Australia -- One day, a giant wave traveling at 200 kilometers per hour across open water could crash into Sydney harbor, wipe out the beaches of California or plow across the golf courses of northeast Scotland.

Mega-tsunamis have happened with greater frequency than modern science would like to believe, and no coastline in the world is safe, says Canadian geologist-geographer Edward Bryant.

Bryant said he had found signs of giant waves sweeping over 130 meter-high headlands in southeast Australia, roaring down the U.S. West Coast and carving into the bedrock of the Scottish coastline north of Edinburgh.

"I believe St. Andrews golf course is a tsunami deposit," said Bryant, head of geosciences at Wollongong University south of Sydney.

Over the past 2,000 years, tsunamis have officially killed 462,597 people in the Pacific region alone, with the largest toll recorded in the Japanese islands.

Of the top recorded events, the Lisbon earthquake of 1755 is said to have triggered a 15-meter high wave that destroyed the port of Lisbon and caused widespread destruction in southwest Spain, western Morocco and across the Atlantic in the Caribbean.

Modern science blames the killer waves on earthquakes, and most countries believe they are immune.

But in his book, "Tsunamis -- The Underrated Hazard," Bryant argues that submarine landslides, underwater volcanoes and even the potentially catastrophic scenario of a meteorite impact must also be taken into account when evaluating tsunami risk.

That means a destructive tsunami moving at 250 meters per second in deep water, 85 meters per second across continental shelves and at 10 meters per second at shore could strike an unprotected coastal metropolis anywhere, killing thousands.

In 1989, Bryant was dabbling into the coastal evolution of rock platforms and sand barriers along the coastline of eastern Australia when he noticed something strange.

Giant boulders, some the size of boxcars and weighing almost 100 tons, were jammed 33 meters above sea level into a crevice at the top of a rock platform sheltered from storm waves.

Further field work found gravel dunes on a 130-meter-high headland and other massive boulders more than 100 meters inland.

This could not be explained by normal wave action or storms.

"But a tsunami could do this," Bryant said.

To the scorn of many modern scientists, Bryant says it is "naive" to base what we know about tsunamis simply on documented history.

In North America and Australia, official history only goes back as far as white colonization. We may be ignoring the legends of the Indians of North America, the Aborigines of Australia or the Maoris of New Zealand at our peril, he said.

One Aboriginal tale tells how one of the four pillars holding up the sky collapsed in the east and the sea also fell in.

Using dating techniques, Bryant argues there is evidence that eastern Australia was struck by a mega-tsunami around 1500, which would coincide with the Aboriginal tale of a "great white wave."

Bryant said Japanese researchers probing past tsunamis had found evidence of a massive earthquake off Oregon in 1700 that would coincide with the Indian tales and with a Pacific seismic zone where the Juan de Fuca tectonic plate grinds under the North American plate in a process called subduction.

"We now know the Oregon subduction zone goes every 300 years. First, 1700, now 2002?" he wonders with raised eyebrows.

What's more, he has found signs that tsunamis have struck the New South Wales coast with alarming regularity every 500 years.

Chile, Japan and Hawaii already have warning systems and evacuation drills. Seabed sensors can send tsunami warnings via satellite triggering bells, alarms and telephones within minutes.

"The only guarantee or prediction is that they will happen again, sometime soon, on a coastline near you," Bryant said.