Real Tsunami May Have Inspired Legend of Atlantis
Like sound or light waves, tsunamis have a wavelength, crests and troughs that could be cancelled out to effectively cloak, say, an oil rig and protect it from the waves, based on new technology. But practically pulling such complex cloaking off will require a lot more research.
The volcanic explosion that obliterated much of the island that might have inspired the legend of Atlantis apparently triggered a tsunami that traveled hundreds of miles to reach as far as present-day Israel, scientists now suggest.
The new findings about this past tsunami could shed light on the destructive potential of future disasters, researchers added.
The islands that make up the small circular archipelago of Santorini, roughly 120 miles (200 km) southeast of Greece, are what remain of what once was a single island, before one of the largest volcanic eruptions in human antiquity shattered it in the Bronze Age some timebetween 1630 B.C. to 1550 B.C.
Speculation has abounded as to whether the Santorini eruption inspired the legend of Atlantis, which Plato said drowned in the ocean. Although the isle is often regarded as just an invention, the explosion might have given rise to the story of a lost empire by helping to wipe out the real-life Minoan civilization that once dominated the Mediterranean, from which the myth of the bull-headed 'minotaur' comes.
The primary means by which the eruption potentially wreaked havoc on the Minoan civilization is by the giant tsunami it would have triggered. However, the precise effects of this eruption and killer wave have been a mystery for decades.
Now scientists find the tsunami may have been powerful enough to race some 600 miles (1,000 km) from Santorini to reach the farthest eastern shores of the Mediterranean, leaving behind a layer of debris more than a foot thick by the coast of Israel.
Researchers dove as far as 65 feet deep (20 meters) off the coast of Caesarea in Israel to collect tubes of sediment, or cores, more than 6 feet long (2 meters) from the seabed.
"The work resembles a construction site with pneumatic hammers, heavy weights, floats to counter-weight equipment, hoses — Each time we took the system down it took hours of surface preparation, planning, and discussion," said researcher Beverly Goodman, a marine geoarchaeologist at Interuniversity Institute for Marine Sciences at Eilat, Israel.
Within the cores, they found evidence of up to nearly 16 inches of sediment deposited roughly about the date of the Santorini eruption. The range of sizes of the particles making up this deposit is the kind one might find laid down by a tsunami — storms, in comparison, cannot kick up the seafloor as much, and as such the range of particle sizes they generate is more limited.
The discovery was very much an accident, Goodman noted. They were actually researching the demise of the harbor of ancient Caesarea, the cause of which remains hotly debated, with culprits including earthquakes and tsunamis.
"I was testing how two later Roman and Byzantine tsunami deposits could be characterized by studying the different grain sizes — various sand, pebbles, rocks, ceramic pieces — in the deposit. Based on determining this 'signature,' I then noticed that there were more than the expected number of tsunami deposits," she explained. "I had no expectation that remnants of the Santorini event would be present in the cores."
These findings support the idea that the Santorini eruption and the side effects from it, such as the tsunami, were massive.
"In the case of the eastern Mediterranean, there seems to be a surprising dearth of archaeological sites along the coastline following the Santorini eruption event," Goodman said. Either archaeologists have failed to concentrate on this time span, "which isn't the case," she said, or the tsunami had a very real impact on coastal settlements.
The dramatic changes in life triggered by the tsunami "might have been part of the fabric of the Atlantis story," Goodman added. "The network of sea-based trade was rather sophisticated in that period, and colonies that were nearly solely dependent on those trade routes existed. It is hard to imagine that such a far-reaching disaster didn't cause them severe shortages in supplies, wealth and power."
Although Atlantis itself "is a myth and legend, it is informative about the experiences of the ancients," Goodman said. "It may very well be the case that those passing the story on had heard of or witnessed events in which coastal buildings went underwater because of earthquakes; beachfront towns were flooded during tsunamis; islands were created by underwater volcanic activity. There may be that grain of truth that lent legitimacy and a certain reality to the legend of Atlantis."
To better reconstruct the Santorini tsunami, the scientists plan to analyze deposits closer to the eruption, such as on Crete and in western parts of Turkey. Knowing the potential effect of tsunamis could be critical for the coastal planning and management, Goodman said, adding that the eastern Mediterranean is very highly populated and possesses considerable sensitive infrastructure such as power stations.
"I suppose there is always the question of whether I think another tsunami will occur in the eastern Med," Goodman said. "The answer is yes. I actually checked the elevation of the house I am moving to near Caesarea before agreeing to move there."
Goodman and her colleagues detailed their findings in the October issue of the journal Geology.
Tsunamis in History
Some of the biggest, most destructive and deadliest tsunamis on record:
8,000 years ago: A volcano caused an avalanche in Sicily 8,000 years ago that crashed into the sea at 200 mph, triggering a devastating tsunami that spread across the entire Mediterranean Sea. There are no historical records of the event – only geological records – but scientists say the tsunami was taller than 10-story building.
Nov. 1, 1755: After a colossal earthquake destroyed Lisbon, Portugal and rocked much of Europe, people took refuge by boat. A tsunami ensued, as did great fires. Altogether, the event killed more than 60,000 people.
Aug. 27, 1883: Eruptions from the Krakatoa volcano fueled a tsunami that drowned 36,000 people in the Indonesian Islands of western Java and southern Sumatra. The strength of the waves pushed coral blocks as large as 600 tons onto the shore.
June 15, 1896: Waves as high as 100 feet (30 meters), spawned by an earthquake, swept the east coast of Japan. Some 27,000 people died.
April 1, 1946: The April Fools tsunami, triggered by an earthquake in Alaska, killed 159 people, mostly in Hawaii.
July 9, 1958: Regarded as the largest recorded in modern times, the tsunami in Lituya Bay, Alaska was caused by a landslide triggered by an 8.3 magnitude earthquake. Waves reached a height of 1,720 feet (576 meters) in the bay, but because the area is relatively isolated and in a unique geologic setting the tsunami did not cause much damage elsewhere. It sank a single boat, killing two fishermen.
May 22, 1960: The largest recorded earthquake, magnitude 8.6 in Chile, created a tsunami that hit the Chilean coast within 15 minutes. The surge, up to 75 feet (25 meters) high, killed an estimated 1,500 people in Chile and Hawaii.
March 27, 1964: The Alaskan Good Friday earthquake, magnitude between 8.4, spawned a 201-foot (67-meter) tsunami in the Valdez Inlet. It traveled at over 400 mph, killing more than 120 people. Ten of the deaths occurred in Crescent City, in northern California, which saw waves as high as 20 feet (6.3 meters).
Aug. 23, 1976: A tsunami in the southwest Philippines killed 8,000 on the heels of an earthquake.
July 17, 1998: A magnitude 7.1 earthquake generated a tsunami in Papua New Guinea that quickly killed 2,200.
Dec. 26, 2004: A colossal earthquake with a magnitude between 9.1 and 9.3 shook Indonesia and killed an estimated 230,000 people, most due to the tsunami and the lack of aid afterward, coupled with deviating and unsanitary conditions. The quake was named the Sumatra-Andaman earthquake, and the tsunami has become known as the 2004 Indian Ocean tsunami. Those waves traveled the globe – as far as Nova Scotia and Peru.
Mystery of Deadly 1946 Tsunami Deepens
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 The tsunami of April 1, 1946 broke over Pier No. 1 in Hilo Harbor, Hawaii. The man in the foreground (lower left) became one of the 159 deaths on the islands.Credit: NOAA |
On April Fools Day in 1946 an earthquake off the coast of the Aleutian Islands in Alaska spawned a series of waves known as a tsunami. One wave as high as a 13-story building hit locally. Others raced across the Pacific, killing dozens and leaving a trail of destruction that stretched to California and even South America.
The earthquake was too small to spawn the huge local wave, many scientists agree, and they have struggled for decades to figure out what happened. The leading theory has been that the earthquake triggered an underwater landslide, generating a one-two punch
Sumatran Quake Left 'Scar' on Earth's Gravity
The devastating 2004 Sumatran earthquake, which caused the worst tsunami in modern times, should have left a detectable scar on Earth's gravity field, European scientists said Monday.
A satellite planned for launch next year could detect the blemish, they said.
The magnitude 9.3 earthquake has already been said to have shortened the day by fractions of a second, shifted the North Pole by an inch, and made the planet less fat around the middle.
The new prediction comes from Roberto Sabadini and Giorgio Dalla Via at the University of Milan. The idea is fairly straightforward. The strength of Earth's gravity varies depending on the depth of a trench or height of a mountain, as well as the density of material. Even changing tides alter the gravity field.
The Dec. 26, 2004 quake lifted an 18-foot (6 meter) ledge along a 620-mile (1,000 kilometer) fault.
Gravity variations are measured using the geoid, which is similar to sea-level. The geoid is a hypothetical "surface" around the Earth at which the planet's gravitational pull is the same everywhere. Over dense areas, the geoid moves away from the real surface, and where gravity is less, the geoid moves closer to the real surface.
The Sumatran quake, the geoid moved as much as 0.7 inches (18 millimeters), the scientists predict.
The variations in the gravity field are already studied from space with NASA's GRACE mission.
The European Space Agency's Gravity Field and Ocean Circulation Explorer (GOCE), planned to launch in 2006, is designed to be very sensitive to minor differences. As the spacecraft passes over regions of stronger and weaker gravitational pull, it will bob up and down.
A study of gravity scar data could in turn refine estimates of the physical rupture of a fault.
"Seismology is good for detecting the slip of earthquake faults and the location of the epicenter, geoid monitoring can determine how much mass is actually being moved around," Sabadini said.
A satellite planned for launch next year could detect the blemish, they said.
The magnitude 9.3 earthquake has already been said to have shortened the day by fractions of a second, shifted the North Pole by an inch, and made the planet less fat around the middle.
The new prediction comes from Roberto Sabadini and Giorgio Dalla Via at the University of Milan. The idea is fairly straightforward. The strength of Earth's gravity varies depending on the depth of a trench or height of a mountain, as well as the density of material. Even changing tides alter the gravity field.
The Dec. 26, 2004 quake lifted an 18-foot (6 meter) ledge along a 620-mile (1,000 kilometer) fault.
Gravity variations are measured using the geoid, which is similar to sea-level. The geoid is a hypothetical "surface" around the Earth at which the planet's gravitational pull is the same everywhere. Over dense areas, the geoid moves away from the real surface, and where gravity is less, the geoid moves closer to the real surface.
The Sumatran quake, the geoid moved as much as 0.7 inches (18 millimeters), the scientists predict.
The variations in the gravity field are already studied from space with NASA's GRACE mission.
The European Space Agency's Gravity Field and Ocean Circulation Explorer (GOCE), planned to launch in 2006, is designed to be very sensitive to minor differences. As the spacecraft passes over regions of stronger and weaker gravitational pull, it will bob up and down.
A study of gravity scar data could in turn refine estimates of the physical rupture of a fault.
"Seismology is good for detecting the slip of earthquake faults and the location of the epicenter, geoid monitoring can determine how much mass is actually being moved around," Sabadini said.
Towering Ancient Tsunami Devastated the Mediterranean
Maximum wave crests heights predicted by a computer simulation of the ancient event. Blue lines are arrival times of the first tsunami waves.
A volcano avalanche in Sicily 8,000 years ago triggered a devastating tsunami taller than a 10-story building that spread across the entire Mediterranean Sea, slamming into the shores of three continents in only a few hours [image].
A new computer simulation of the ancient event reveals for the first time the enormity of the catastrophe and its far-reaching effects [video].
The Mt. Etna avalanche sent 6 cubic miles of rock and sediment tumbling into the water—enough material to cover the entire island of Manhattan in a layer of debris thicker than the Empire State Building is tall.
The mountain of rubble crashed into the water at more than 200 mph. It pummeled the sea bed, transformed thick layers of soft marine sediment into jelly and triggered an underwater mudslide that flowed for hundreds of miles.
Recreating an ancient disaster
To create their computer simulation, researchers at the National Institute of Geophysics and Volcanology in Italy used sonar-equipped boats to survey seafloor sediment displaced by the Mt. Etna avalanche.
Their recreation suggests the tsunami's waves reached heights of up to 130 feet and maximum speeds of up to 450 mph, making it more powerful than the Indonesian tsunami that killed more than 180,000 people in 2004.
The researchers have also linked the ancient tsunami with the mysterious abandonment of Atlit-Yam, a Neolithic village located along the coast of present-day Israel. When archeologists discovered the village about 20 years ago, they found evidence of a sudden evacuation, including a pile of fish that had been gutted and sorted but then left to rot.
"A tsunami was not suspected before," lead researcher Maria Pareschi told LiveScience.
Could happen today
According to Pareschi, if the same tsunami struck today, Southern Italy would be inundated within the first 15 minutes [image]. In one hour, the waves would reach Greece's western coasts. After an hour and a half, the city of Benghazi in Northern Africa would be hit. At the three and a half hour mark, the waves would have traversed the entire Mediterranean to reach the coasts of Israel, Lebanon and Syria.
Avalanches and minor eruptions still occur on Mt. Etna today, but so far, nothing approaching the magnitude of the ancient event.
"Should the Neolithic Etna tsunami have occurred today, the impact is tremendous because the Eastern Mediterranean coasts are very inhabited ones," Pereschi said.
A new computer simulation of the ancient event reveals for the first time the enormity of the catastrophe and its far-reaching effects [video].
The Mt. Etna avalanche sent 6 cubic miles of rock and sediment tumbling into the water—enough material to cover the entire island of Manhattan in a layer of debris thicker than the Empire State Building is tall.
The mountain of rubble crashed into the water at more than 200 mph. It pummeled the sea bed, transformed thick layers of soft marine sediment into jelly and triggered an underwater mudslide that flowed for hundreds of miles.
Recreating an ancient disaster
To create their computer simulation, researchers at the National Institute of Geophysics and Volcanology in Italy used sonar-equipped boats to survey seafloor sediment displaced by the Mt. Etna avalanche.
Their recreation suggests the tsunami's waves reached heights of up to 130 feet and maximum speeds of up to 450 mph, making it more powerful than the Indonesian tsunami that killed more than 180,000 people in 2004.
The researchers have also linked the ancient tsunami with the mysterious abandonment of Atlit-Yam, a Neolithic village located along the coast of present-day Israel. When archeologists discovered the village about 20 years ago, they found evidence of a sudden evacuation, including a pile of fish that had been gutted and sorted but then left to rot.
"A tsunami was not suspected before," lead researcher Maria Pareschi told LiveScience.
Could happen today
According to Pareschi, if the same tsunami struck today, Southern Italy would be inundated within the first 15 minutes [image]. In one hour, the waves would reach Greece's western coasts. After an hour and a half, the city of Benghazi in Northern Africa would be hit. At the three and a half hour mark, the waves would have traversed the entire Mediterranean to reach the coasts of Israel, Lebanon and Syria.
Avalanches and minor eruptions still occur on Mt. Etna today, but so far, nothing approaching the magnitude of the ancient event.
"Should the Neolithic Etna tsunami have occurred today, the impact is tremendous because the Eastern Mediterranean coasts are very inhabited ones," Pereschi said.
How Tsunamis Work
A major earthquake that struck Chile overnight has sent a tsunami out into the Pacific Ocean, prompting a tsunami watch along the coasts of California and parts of Alaska and a tsunami warning for Hawaii.
A watch is a cautionary statement that does not mean waves are imminent. Officials are not sure what nations could be affected bytsunami, but they caution that the entire Pacific Basin is at risk.
A warning, as issued for Hawaii, means waves are imminent and residents should seek high ground. Early reports of waves exceeding 7 feet have been reported near the epicenter of the earthquake. The 8.8-magnitude temblor was centered offshore, 200 miles (325 km) southwest of Santiago, Chile.
A tsunami has been generated that could cause damage along coastlines of all islands in the state of Hawaii," according to a bulletin from NOAA, the parent organization of the National Weather Service. The waves would be expected to reach Hawaii starting at 11:19 a.m. local time.
Other than timing, however, tsunamis are highly unpredictable.
How tsunamis work
A tsunami is not a single wave, but a series that behave much like the waves rippling out from a stone dropped in a pond. Each wave can last five to 15 minutes, and the danger can last for hours after the initial wave arrives.
"Tsunami waves heights cannot be predicted and the first wave may not be the largest," according to today's NOAA statement.
Tsunamis, which can travel over the ocean surface from many hundreds of miles, can be generated when chunks of the planet's crust separate under the seafloor, causing an earthquake. Here's what happens: One slab of lifting crust essentially rapidly acts as a giant paddle, transferring its energy to the water.
Tsunamis can also be caused by volcanic eruptions, underwater detonations and even landslides.
The resulting waves are hard to predict for several reasons. Nobody knows how a quake has affected the seafloor until hours, days or even months after the event. And a tsunami is almost imperceptible on the open ocean, rising to full ferocity only as it nears the shore.
While more tsunami-sensing buoys cover the ocean than before the devastating 2004 Indian Ocean tsunami, these waves can still be missed.
Not all seafloor earthquakes will generate a tsunami — if the friction between the crustal plates occurs very deep below the ocean floor or move in a way that causes a minimal paddle effect, a tsunami isn't as likely to form.
Major tsunamis in history
The 2004 quake just off the coast of Sumatra, Indonesia, was colossal, eventually put at magnitude 9.3. But an 8.7-magnitude earthquake in 2005 that originated at the same location, while large enough to generate a devastating tsunami, scientists say, did not do so. The exact reasons remain mysterious.
The 2004 tsunami, and those spurred by the 9.2-magnitude Great Alaska Earthquake in 1964, were examples of teletsunamis, which can cross entire oceans.
Several devastating tsunamis have occurred throughout recorded history, including one that leveled Lisbon, Portugal in 1755 and one generated by the explosion of Krakatoa in Indonesia that drowned an estimated 36,000 people.
Except for the largest tsunamis, such as the 2004 Indian Ocean event, most tsunamis do not result in giant breaking waves; instead they come in much like very strong and fast-moving tides, according to the U.S. Geological Survey. As a tsunami nears the shoreline, the rising seafloor forces a wave that might have been just inches tall into a monster that can be several feet high.
The Pacific Ocean basin is particularly prone to tsunamis. Last year, a study of earthquake faults off the coast of Alaska predicted that the risk of tsunamis for the U.S. West Coast is higher than had been thought. Previous research found that a major tsunami hitting Southern California could cause $42 billion in damage.
A watch is a cautionary statement that does not mean waves are imminent. Officials are not sure what nations could be affected bytsunami, but they caution that the entire Pacific Basin is at risk.
A warning, as issued for Hawaii, means waves are imminent and residents should seek high ground. Early reports of waves exceeding 7 feet have been reported near the epicenter of the earthquake. The 8.8-magnitude temblor was centered offshore, 200 miles (325 km) southwest of Santiago, Chile.
A tsunami has been generated that could cause damage along coastlines of all islands in the state of Hawaii," according to a bulletin from NOAA, the parent organization of the National Weather Service. The waves would be expected to reach Hawaii starting at 11:19 a.m. local time.
Other than timing, however, tsunamis are highly unpredictable.
How tsunamis work
A tsunami is not a single wave, but a series that behave much like the waves rippling out from a stone dropped in a pond. Each wave can last five to 15 minutes, and the danger can last for hours after the initial wave arrives.
"Tsunami waves heights cannot be predicted and the first wave may not be the largest," according to today's NOAA statement.
Tsunamis, which can travel over the ocean surface from many hundreds of miles, can be generated when chunks of the planet's crust separate under the seafloor, causing an earthquake. Here's what happens: One slab of lifting crust essentially rapidly acts as a giant paddle, transferring its energy to the water.
Tsunamis can also be caused by volcanic eruptions, underwater detonations and even landslides.
The resulting waves are hard to predict for several reasons. Nobody knows how a quake has affected the seafloor until hours, days or even months after the event. And a tsunami is almost imperceptible on the open ocean, rising to full ferocity only as it nears the shore.
While more tsunami-sensing buoys cover the ocean than before the devastating 2004 Indian Ocean tsunami, these waves can still be missed.
Not all seafloor earthquakes will generate a tsunami — if the friction between the crustal plates occurs very deep below the ocean floor or move in a way that causes a minimal paddle effect, a tsunami isn't as likely to form.
Major tsunamis in history
The 2004 quake just off the coast of Sumatra, Indonesia, was colossal, eventually put at magnitude 9.3. But an 8.7-magnitude earthquake in 2005 that originated at the same location, while large enough to generate a devastating tsunami, scientists say, did not do so. The exact reasons remain mysterious.
The 2004 tsunami, and those spurred by the 9.2-magnitude Great Alaska Earthquake in 1964, were examples of teletsunamis, which can cross entire oceans.
Several devastating tsunamis have occurred throughout recorded history, including one that leveled Lisbon, Portugal in 1755 and one generated by the explosion of Krakatoa in Indonesia that drowned an estimated 36,000 people.
Except for the largest tsunamis, such as the 2004 Indian Ocean event, most tsunamis do not result in giant breaking waves; instead they come in much like very strong and fast-moving tides, according to the U.S. Geological Survey. As a tsunami nears the shoreline, the rising seafloor forces a wave that might have been just inches tall into a monster that can be several feet high.
The Pacific Ocean basin is particularly prone to tsunamis. Last year, a study of earthquake faults off the coast of Alaska predicted that the risk of tsunamis for the U.S. West Coast is higher than had been thought. Previous research found that a major tsunami hitting Southern California could cause $42 billion in damage.
Tsunami Special Report
The earthquake and tsunami of Dec. 26, 2004 combined to create a disaster in Asia that is among the worst in recorded history. Though significant tsunamis are rare, it was not the first event of its kind.
Tsunamis have proven incredibly deadly in the past. In 1896 a tsunami caused 27,000 deaths in Japan. A combination of earthquake, fire and tsunami centered around Lisbon, Portugal killed 60,000 people in 1755.
Just two weeks before the Asian catastrophe, scientists revealed the threat of a megatsunami in the Pacific Ocean that could be triggered by a subsea landslide. In recent days, other researchers warned of the potential for a 9.0-magnitude earthquake and tsunami that could hit the West Coast of the United States. There is a warning system in the Pacific, and now officials in India plan to set one up. Also, the United States now is planning to set up a global tsunami warning system.
Tsunamis from near-shore earthquakes can begin striking a coast within minutes, however.
For a tsunami triggered by an earthquake in the Cascadia fault zone off the U.S. West Coast, some residents would have about 15 minutes to get to high ground, says Robert Yeats, professor emeritus of geosciences at Oregon State University.
Should you worry? While coastal residents ought to be aware of the threat, experts say, there are many other things to worry about. Heart disease, accidents, war, famine, disease and shootings are far more likely killers than anything Nature dishes out.
Just two weeks before the Asian catastrophe, scientists revealed the threat of a megatsunami in the Pacific Ocean that could be triggered by a subsea landslide. In recent days, other researchers warned of the potential for a 9.0-magnitude earthquake and tsunami that could hit the West Coast of the United States. There is a warning system in the Pacific, and now officials in India plan to set one up. Also, the United States now is planning to set up a global tsunami warning system.
Tsunamis from near-shore earthquakes can begin striking a coast within minutes, however.
For a tsunami triggered by an earthquake in the Cascadia fault zone off the U.S. West Coast, some residents would have about 15 minutes to get to high ground, says Robert Yeats, professor emeritus of geosciences at Oregon State University.
Should you worry? While coastal residents ought to be aware of the threat, experts say, there are many other things to worry about. Heart disease, accidents, war, famine, disease and shootings are far more likely killers than anything Nature dishes out.
