Exactly one hundred years ago, Greek and French archaeologists uncovered the remains of a "prehistoric Pompeii" deep under the ashen surface of the Greek island of Thera in the Cyclades. What they saw then was extraordinary—houses still standing to the roof, with windows overlooking the sea, frescoes on the walls, grain in the granaries, painted vases and stone tools, bones of animals and branches of trees, and a little old man caught in the Bronze Age disaster of Thera. Nineteenth-century scientists felt a childlike wonder at this glimpse of daily life from an era so ancient they could not identify it.
Thera is the most southerly of the Cycladic islands, which fill the Aegean Sea between Greece and Crete. It is an active volcano, near a major earthquake fault, and during its violent past the whole central mass of the island has blown high in the air, once or perhaps twice, and fallen back in again. After long discharges of ash, in about 23,000 B.C. and 1500 B.C. it seems that the normal volcanic outlets became plugged, and super-hot gas-charged magma burst up from under the earth through a solid cap of island, throwing huge boulders fifty kilometers in the air and scattering hot ash, or tephra, over the whole eastern Mediterranean. When the magma chamber under the earth drained out, the remaining pillars of matter were too fragile to stand, and everything collapsed into the new hollow with a huge inrush of sea. This invasion of water was accompanied by a trembling of the earth, incredible noise, 150-foot tidal waves, electrified atmosphere, gales, steam, sulfuric mist, and showers of ash which barred the sunlight and turned much of the world dark. In 1500 B.C., when the Mediterranean was densely inhabited by highly civilized people, the eruption of Thera must have caused a shocking amount of physical damage and mental agony on all the neighboring coasts.
As you sail into the caldera of Thera now you quickly sense the presence of a natural power too demonic to understand neatly. The whole island is volcanic sculpture, layers of pale ash and pumice thrown up from inside the earth to mask the original limestone flanks of the island mountain. Only the rim of the crater survives, sheer cliffs of ash rising 1200 feet above the sea, layered in tones of rose and tan and white, broken by bizarre bastions of tougher debris, held between a bed of black lava below and a coating of vineyards and white villages above.
The circle of the crater is broken three times, once in the north and twice in the west, where the sea has flowed in to isolate the little block of Aspronisi, the longer arc of Therasia. The whole gap, four times larger than the hole the volcano of Krakatoa made in itself when it blew up the Sunda Straits in 1883 and staggered the world, is four miles across and 1200 feet deep. Three volcanic islets, the Kameni, or Burnt Ones, grow slowly in the center, steaming gently and oozing brown lava, warming the sea and attracting sharks.
The last major eruption of Thera took place in 1925, and there were minor convulsions in 1928, 1939, and 1950. Between convulsions earthquakes rock the island. Thousands of islanders left after the quake of 1956, which killed scores in falling rock, smashed the villages, and expelled the sea nearly a thousand feet from the coasts. One admires the Therans who stay. It would be interesting to explore their deeper thoughts about life on a volcano, and to assess the quality of their childhood terrors. Yet Greeks are full of courage and disconcerting honesty; they are used to the threats of nature. From day to day they are more concerned with poverty than with forces under the earth.
Thera is not rich, although some individuals are. Rain scarcely falls there. There is only one hillside brook, springing from the one big limestone hill to project above the ash, Prophet Elias, which carries the gray stone city of classical Thera on one peak and a white monastery on the other. Elsewhere people depend on cisterns and on black bags of water towed in by boat. In this dry land the houses are paradoxically damp because they are partly hollowed out of the cliffs like troglodyte caves, vaulted free-form honeycombs where the sun never reaches. The volcanic soil is good for acid fruits—small tomatoes, and the grapes which make the famous Santorini wine. Both crops are troublesome. The wind blows so hard that the grapes cannot be propped up to catch the sun; the wine is too sweet to sell abroad much.
Transportation depends on a few old Fords and an army of donkeys. Only donkeys can manage the hairpin stone trails from the landing stages to the towns a thousand feet above. In this flat, sheared-off country without earth, water, or trees it is hard to make a living. The villagers say their income often does not exceed $60 a year to feed a family of four, although in good years they may make $200. In such an economy men go to sea, or wait on tourists, or mine pumice.
The prehistoric ruins of Thera were first exposed over a century ago in the pumice mines. French engineers for Suez realized that Thera provided a prime cheap source of cement for the canal and the installations of Port Said. They started open-air mines in the huge deposit of ash south of the main town of Phirá, on the southern tip of Therasia, and at scattered points around the circumference of the island wherever ships could come in close. Houses all over the Middle East are still built out of Thera.
The white volcanic ash when mixed with chalk makes a fine hard waterproof concrete; the wetter it gets the harder it grows. The pumice, which comes in pale porous nuggets or chunks, is exported raw and ground at its destination for building, industrial abrasives, and cleaning inky fingers. Some dentists use it too, though most American teeth are cleaned by Italian volcanoes. Freighters moor close under the cliffs where wooden chutes carry the volcanic glass, crashing a thousand feet, down into the waiting holds. One foreman with forty years' experience in the mines, Mr. Savvas, has watched a solid half mile of Thera sent overseas since his boyhood, and like his predecessors, he has seen innumerable traces of ancient civilization chewed up by commerce. The men are so used to the world underneath the ash that they scarcely pay attention to it anymore.
The mines of Phirá make a wild white landscape which grows eerie at noon under the sun's heat. The crucial level for prehistory lies between 90 and 120 feet down, where a layer of weathered brown lava was the surface of Thera in the second millennium B.C. House walls are tossed aside in wavering lines by the machines; pottery and plaster litter the ground. The miners often see wood—parts of Cycladic houses or simply the trees which once grew in the fields. A few years back a wild almond with bark and leaves excited much comment but was not saved.
Exploration started in the mines across the caldera on Therasia. A maze of walls appeared under the property of Mr. Alaphousos, "a foreigner from the other side of the island." The professor of chemistry in Athens Christomanos saw them and understood their significance; the distinguished Theran Dr. Nomikos joined Alaphousos in exploring them. The Greek scientists were vastly curious about how so much volcanic matter had arrived on top of constructions which were clearly very primitive, but the danger of the site hampered their investigations. Cascades of loose pumice kept rolling down to threaten them with live burial.