While Santorini continues to shake by ongoing earthquakes in the island’s caldera, overbuilding has turned its fragile soil into hollow ground. The situation is worsened by the dangerous slopes of the terrain, which favor landslides, while the constant tremors multiply the risks for both legal and illegal buildings, raising concerns among residents and scientists alike.
The President of the Earthquake Planning and Protection Organization (OASP), Professor of Dynamic Tectonics and Geology at the University of Athens, Efthymios Lekkas, stated: “The caldera of Santorini contains buildings with a high vulnerability index. On the one hand, due to the steep slopes, which reach up to 60%, seismic activity increases by up to 170% above the values predicted by the Seismic Code and European regulations. On the other hand, construction continues unabated, both legally and illegally.”
The professor added that construction in the caldera continues to expand downward, despite a law intended to ban construction on public land, which was supposed to pass through Parliament but never did. “As a result, uncontrolled building continues,” he noted.
Indeed, some people’s ingenuity is remarkable. Investors resort to illegal practices, building hotels on plots of land even in areas of the island where tourism facilities have been prohibited since the 1990 Presidential Decree.
A local architect, who has worked as a consultant on urban planning for the Ministries of the Aegean and Environment, emphasizes that hotel owners will go to any lengths to ensure a good view for their buildings. She cites a constructor who dug an underground tunnel to create rooms facing the caldera on public land, despite his plot not being on the caldera side but across from it. “He made a tunnel and… found a view,” the architect noted.
The list of building violations and improper land use on Santorini is extensive. Despite the proposed Special Urban Planning Scheme (EUPS) for the island significantly limiting construction (currently, 62% of the island is designated for residential development, which will be reduced to 12%, and 4.9% for tourism facilities), both the local government and professional organizations on the island are calling for even stricter restrictions.
The plan proposes a complete ban on construction in the caldera specifically. Recent data highlights the growing scale of illegal construction and reveals significant discrepancies in the built-up area per resident. While the average built-up area in island regions typically ranges between 40 and 80 square meters per resident, Santorini shows alarming figures. In Imerovigli, for example, the built-up area per resident reaches 278.62 square meters, of which 105.7 square meters are illegal.
Konstantinos Spyros, an Emeritus Professor of Structural Engineering at NTUA, also emphasizes the dangers, especially for the older buildings in the caldera. As the professor explained, the majority were built before 1990, meaning they lack modern seismic regulations.
Furthermore, due to the slope of the land—especially for buildings with unobstructed views at the caldera’s edge—these structures experience higher seismic loads, requiring designs that account for increased seismic acceleration. Finally, he points out that several buildings located below the crater’s rim, near the sea, are even more at risk of landslides.
The island of Santorini and the surrounding region have experienced 12 thousand earthquakes.
