The island is located on top of the volcanic arc of the Aegean Sea which consists of a series of inactive or active volcanoes spanning approximately 500 km in length and 30-40 km in width. The arc extends from the eastern coast of Greece's mainland, through to central Aegean Sea and ends at the western coast of Turkey.
The geology of Santorini presents a large variety and wealth.
Prevolcanic are the limestone layers in Prophet Εlias, Monolithos, Gavrilos and the shale rocks in Athinios. Volcanic are the pyroclastic, the lava and the thick layers of Theran earth, which consist the ground of the island. It is as thick as 40 m in the flat land but it is thinner in highlands due to corrosion. It is fertile and favors crops where the economy of the island was based on prior to the development of tourism. Vines, cereals (barley mainly), legumes, fava and, in the older days, cotton have been the basic crops from ancient times.
Santorini is one of the most arid regions of the Aegean Sea, due to lack in underground wells and to very few rainfalls. The climate is temperate and the temperatures are quite high during winter, while in the summer the heat mitigates the wind. This time of season fogs keep moisture in the atmosphere, while many times south winds blow.
In its SE part is located the mountain of Prophet Elias with the homonymous monastery.
Next to it is Mesa Vouno where ancient Thera is built.
The eastern side of the island slopes gently to the sea, lined with beaches of black volcanic sand.
Fossilized remains have been found in the geological layers dated before the great eruption of 1600 B.C., giving information on the natural flora of the island: palm, olive and peanut trees, are flora characteristics of all the dry zones in the Mediterranean.
In the excavation of the prehistoric settlement of Akrotiri, carbonized remains of reeds, pine, vine and olive trees have been found, and the cultivated kinds were barley, figs, almonds, lentils, vetch, fava beans and a kind of lupine.
Barley was one of the oldest crops in the island. Seeds and storage vessels have been found in the excavation of Akrotiri. Up until after the war, most of the people fed on barley bread or barley bread rolls, that had been kneaded and cooked every month due to lack in fire wood and use of vine branches and fig wood.
Straw was the basic food for mules and donkeys. At present day, barley is used for animal food production and only a small part is threshed.
In 1840, French traveler Abba Pegues wrote: "Santorini offers an exciting variety of contrasts: the volcanic and rocky mountains, half-cultivated and half-flared rocks, some beautiful and others awful. They are the great gulches shredding the valleys and the fertile slopes, full of vines. They are the neighborhood of the sea embracing the island like a huge valley...”
The vineyard of Thera is one of the most peculiar in the world as is almost everything on this volcanic island of the Aegean Sea. The vines flourish here not only because they can withstand drought but also because they are one of the few wooden plants whose roots can penetrate the Theran land.
For centuries vines and wines have played a fundamental role in the island's economic, social and financial life. The production of the vineyards exceeded the needs of the population, so it was exported, especially at the time shipping had developed.
Local grape varieties produce high quality wines that fully express Santorini's unique ecosystem.
The cultivated area begins at a height of 300 meters and the vines go all the way down to the level of the sea. The vine dressers built dry stone walls to protect the soil from erosion and to increase the cultivated land.
The vineyard of Santorini is ancient, as are its varieties. Excavation findings in the prehistoric settlement of Akrotiri, reveal that grapes were grown on the island at least since the 17th century BC. Wine cultivation, wine making and wine trade were important activities for the habitants.
The prehistoric vineyard was destroyed by the great volcanic eruption around 1600 BC. According to Herodotus, the first colonists that went to Santorini after the disaster were the Phoenicians, who, as well as the ones that followed, cultivated various plants, but only vines managed to survive over the centuries in this inhospitable environment.
The new igneous soil gave birth to another vineyard, around 1200 BC. Therefore, we wouldn't exaggerate if we said that it is more than 3,200 years old, since it has been cultivated non-stop during all this time.
The vines of Santorini are real works of art, and their ancient pruning technique is quite exceptional. To protect plants from strong winds and to limit their need for water, the vine dressers of the island adopted and refined a primitive pruning technique, called "kouloura".
The plants are pruned to form a low vegetable basket where grapes are protected and mature, without run the risk of being damaged by sand, which is carried by the wind. According to oenologist Angeliki Georgantopoulou, the fine sandy soil, poor in nutritious ingredients, with low argil content protected Santorini's vineyard from vine louse (phylloxera). Today they are one of the few self-rooted vineyards in Europe.
* Source: "Santorini: And the sea brought forth the earth"/ Topio Publications/ from the text of archeologist Kiki Birtacha.