Did a Tsunami Wipe Out a Cradle of Western Civilization?

Like the Indian Ocean disaster, this wave was a mass killer.

By Evan Hadingham|Friday, January 04, 2008
minos_temple
minos_temple
Remains of King Minos's temple still stand in Knossos.
Image courtesy of Evan Hadingham

The effects of the Indian Ocean tsunami of December 2004 are only too well known: It knocked the hell out of Aceh Province on the Indonesian island of Sumatra, leveling buildings, scattering palm trees, and wiping out entire villages. It killed more than 160,000 people in Aceh alone and displaced millions more. Similar scenes of destruction were repeated along the coasts of Southeast Asia, India, and as far west as Africa. The magnitude of the disaster shocked the world.

What the world did not know was that the 2004 tsunami—seemingly so unprecedented in scale—would yield specific clues to one of the great mysteries of archaeology: What or who brought down the Minoans, the remarkable Bronze Age civilization that played a central role in the development of Western culture?

Europe’s first great culture sprang up on the island of Crete, in the Aegean Sea, and rose to prominence some 4,000 years ago, flourishing for at least five centuries. It was a civilization of sophisticated art and architecture, with vast trading routes that spread Minoan goods—and culture—to the neighboring Greek islands. But then, around 1500 B.C., the Minoan world went into a tailspin, and no one knows why.

In 1939, leading Greek archaeologist Spyridon Marinatos pinned the blame on a colossal volcanic eruption on the island of Thera, about 70 miles north of Crete, that occurred about 1600 B.C. The event hurled a plume of ash and rock 20 miles into the stratosphere, turning daylight into pitch darkness over much of the Mediterranean. The explosion was recently estimated to be 10 times as powerful as the 1883 eruption of Krakatau in Indonesia, which obliterated 300 towns and villages and killed at least 36,000 people. So extreme was the Thera eruption that many writers linked it to Plato’s legend of Atlantis, the magnificent island city swallowed up by the sea. Marinatos’s theory was bolstered in 1967 when he dug up the ruins of Akrotiri, a prosperous Minoan town on Thera that had been buried in volcanic ash. Akrotiri became famous as a Bronze Age Pompeii because the ash preserved two-story dwellings, exquisite frescoes, and winding streets almost intact.

On further examination, though, the ruins did not confirm the theory. It turned out that the pottery on Akrotiri was not from the final phase of Minoan culture; in fact, many Minoan settlements on Crete continued to exist for at least a generation or two after the Thera cataclysm. Archaeologists concluded that the Minoans had not only survived but thrived after the eruption, expanding their culture until they were hit by some other, unknown disaster—perhaps some combination of fire, earthquake, or foreign invader. Thera’s impact, it seemed, had been overestimated. But startling new evidence is forcing archaeologists to rethink the full fury of the Thera explosion, the natural disaster it may have triggered, and the nature of the final blow to the once-great Minoan civilization.

Each summer, thousands of tourists encounter the Minoans at the spectacularly restored ruins of Knossos, an 11-acre complex four miles south of Crete’s capital, Heraklion. Late-19th-century excavations by Sir Arthur Evans revealed Knossos to be a vast, intricately engineered, multistory building, complete with flushing toilets, statuettes of bare-breasted priestesses, and frescoes of athletes vaulting over bulls. In 1900, Evans discovered an impressive stone throne, from which he believed the legendary King Minos and his descendants had presided over Bronze Age Crete. In the 1980s, however, a new generation of archaeologists, including Joseph Alexander “Sandy” MacGillivray, a Montreal-born scholar at the British School at Athens, began questioning many of Evans’s assumptions. Smaller-scale versions of Knossos have turned up at nearly every Minoan settlement across Crete, and scholars now suspect there was no single king but rather many independent polities.

MacGillivray also became interested in how the civilization ended. At Palaikastro, in the island’s far northeastern corner, MacGillivray and his colleague Hugh Sackett have excavated seven blocks of a Minoan town of perhaps 5,000 inhabitants, their plastered and painted houses arranged in a network of tidy paved and drained streets. One striking find was the foundations of a fine mansion, paved with fancy purple schist and white limestone and designed around an airy central courtyard “of Knossian pretensions,” as MacGillivray puts it. “But after the house was destroyed by an earthquake, it was abandoned and never rebuilt, and that preserved some things we had a hard time explaining.”

The house was dusted with a powdery gray ash, so irritating that the diggers had to wear face masks. Chemical analysis showed that the ash was volcanic fallout from the Thera eruption, but instead of resting in neat layers, the ash had washed into peculiar places: a broken, upside-down pot; the courtyard’s drain; and one long, continuous film in the main street outside. It was as if a flash flood had hosed most of the ash away, leaving these remnants behind. Some powerful force had also flipped over several of the house’s paving slabs and dumped fine gravel over the walls—but this part of the site lies a quarter of a mile from the sea and far from any stream or river.

That wasn’t the only oddity. Another building “looked like it had been flattened, the whole frontage facing the sea had been torn off, and it made no sense. And we asked ourselves, could a wave have done this?” MacGillivray says.

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The strangest and most significant find, however, was a soil layer down by the beach that looked like nothing MacGillivray had ever seen in four decades as a field archaeologist. A horizontal band of gravel about a foot thick was stuffed with a mad jumble of broken pottery, rocks, lumps of powdery gray ash, and mashed-up animal teeth and bones. Perhaps an exceptionally violent storm had inflicted this chaos, MacGillivray considered, but he began to suspect that a tsunami was the more likely culprit.

mallia
mallia

The statue at Mallia may have been smashed and burned during an uprising against the Minoan elite.

Image courtesy of Evan Hadingham

MacGillivray invited Hendrik Bruins to Palaikastro. The Dutch-born geoarchaeologist and human ecologist had a reputation as a skillful analyst of the thorny dating controversies that beset archaeology in the Middle East, but figuring out the chaotic layer overlooking the beach presented a novel scientific challenge. “Identifying a tsunami deposit is a completely new field,” Bruins explains. “Until the early 1990s, earth scientists didn’t even recognize that tsunamis do more than just destroy the coast—they leave distinctive deposits behind as well. I needed to do a lot of different tests to convince myself, as well as my colleagues, that we were dealing with a tsunami and not something else, like debris from a storm surge.”

Another building looked like it had been flattened. Could a wave have done this?

Bruins sent thin sections of the chaotic deposit to micropaleontologist Chaim Benjamini, a colleague at Ben-Gurion University of the Negev in Israel. Benjamini identified the tiny round shells of foraminifera and fragments of red coralline ­algae; these marine organisms suggested that the ocean, rather than a river or a flash flood, had been involved. If the marine organisms had been scooped up from below sea level and dumped on the elevated promontory, something much bigger than a storm surge must have pounded the coast of ancient Crete.

The strange pattern of gravel deposits in the town offered further evidence of a deep oceanic disturbance. Then there were lumps of gray ash in the beach layer, “resembling unstirred instant-soup lumps at the bottom of a cup,” according to Bruins. He sent samples of these lumps to two state-of-the-art geochemistry labs in Germany, which analyzed the sample’s geochemical signature. The results of both tests were identical: a perfect match between Theran ash and the “soup lumps” on the beach.

Finally, there was the question of when all this disruption occurred. Bruins sent fragments of cattle bones and seashells from the chaotic layer to the radiocarbon dating lab at the University of Groningen in the Netherlands. Because of well-known problems in calibrating dates from 3,500 years ago, he knew the lab would be unable to pin down the exact calendar age of the samples, but the uncalibrated measured age of the cattle bones closely matched the latest equivalent dates for the cataclysm on Thera.

All the clues pointed to one answer: A giant wave had struck Palaikastro Bay while freshly fallen ash from Thera was still lying about, inundating the town for miles inland and streaking it with strange patterns of ash. But could even a giant wave be big enough to wipe out an entire civilization?

MacGillivray consulted Costas Synolakis, an energetic Greek-born earth scientist at the *University of Southern California, where he pioneered the predictive computer model used by the Pacific Tsunami Warning Center in Hawaii. Synolakis’s first attempts to model tsunamis in the early 1990s began as a solitary exercise. Everything changed after the Indian Ocean tsunami of 2004. Synolakis visited Banda Aceh, the city in northwestern Sumatra closest to the epicenter of the undersea quake, where hundred-foot waves had destroyed a city of more than 150,000 people in minutes. “It was a surreal, absurdist landscape,” he says. “It took an effort of imagination to conceive that people had ever lived there.” Almost overnight, Synolakis’s expertise in computer modeling of tsunamis became a focus of worldwide scientific and media attention.

*Correction: January 9, 2008 - this originally incorrectly stated University of California Los Angeles+++
debris
debris
A layer of sediment at Palaikastro, packed with tsunami debris.
Image courtesy of Evan Hadingham

In 2000, Synolakis had con- sulted on a study to model a hypothetical Minoan tsunami. He found that no matter how steep the waves were when they started out at Thera, they dissipated quickly, reaching only three to nine feet at most when they hit Crete, some 70 miles away. The study concluded that such waves could have been “disruptive,” but not devastating, to Minoan Crete.

Synolakis was still thinking that way when he visited Palaikastro in May 2006. Then MacGillivray took him down to the beach. “The moment I looked at that debris layer, I was absolutely stunned,” Synolakis says. “The image that came to me, right then and there, is what I saw everywhere after the December 2004 tsunami: a blanket of cultural debris, broken dishes, broken glass, bits of bone, people’s belongings scattered everywhere. It looked exactly like that kind of debris carpet, and you don’t get it in a smaller tsunami. The presence of this chaotic deposit suggested that the tsunami was at least three or four meters [10 to 13 feet] at the shoreline.” What had begun as a casual visit now turned into a full-blown research project. Synolakis hired a boat and took depth measurements of the seabed in Palaikastro Bay. When he tested the hillside behind the Minoan town to establish how far the wave had penetrated inland, he found what appeared to be more layers of chaotic debris at an astounding 90 feet above sea level.

About 60 miles to the west of Palaikastro, near the palace of Mallia, the research team found yet another strikingly similar chaotic deposit. Plugging in all the new data, Synolakis drastically revised his tsunami model. “When we put it all together,” he says, “we’re looking at a wave that’s on the order of 15 meters [50 feet] when it hits the shore at Palaikastro. This is a gigantic wave, much larger, wider, and longer than we thought; its volume is 10 times more than what we estimated only six years ago. We’re talking about an extreme event, certainly on the order of the 2004 Indian Ocean disaster.”

With eyewitness video of that disaster lingering in everyone’s minds, it took little imagination to visualize the physical destruction that must have hit Palaikastro, Mallia, and elsewhere along the Cretan coast. But evidence suggests that the Minoans survived the disaster for at least a generation or two; the real end came later, in an outbreak of fiery vandalism. Throughout Crete, temple-palaces were burned and ransacked, and there are no obvious signs of battle, invasion, or natural disaster at these ruins. Of all the great Minoan palaces, only Knossos survived; eventually it was taken over by the Mycenaeans, the mainland Greeks who prospered as the fortunes of Crete declined.

A leader of the Palaikastro team, Belgian archaeologist Jan Driessen, contends that the wave of destruction was the tail end of a spiral of instability that the Thera catastrophe set in motion. A steep drop-off in the number of Minoan sites suggests that there had been a famine or an epidemic, one perhaps touched off by the environmental effects of the eruption combined with the later tsunami.

There may have been a spiritual crisis as well. At Palaikastro, archaeologists found that a shrine had been violently destroyed and a cult statuette deliberately smashed and burned. Driessen suggests there may have been a reaction against the religious cult represented by the statuette, perhaps as part of a populist uprising against the elite in their villas and temple-palaces. The loss of life and livelihood after the eruption may have aggravated problems of class difference and widened the gap between the elite and the commoners, which Driessen says “existed already in Minoan society.”

The terrifying scale of the Thera eruption, followed by the devastating force of the giant tsunami it created, may have led to a gradual unraveling of the values and beliefs that had sustained this brilliant civilization for so long. In his poem “The Hollow Men,” T. S. Eliot writes these famous lines: “This is the way the world ends / This is the way the world ends / This is the way the world ends / Not with a bang but a whimper.”

For the Minoans, it appears their world ended with both.

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