On October 30, a 7.0 magnitude earthquake struck the eastern Aegean Sea between Turkey and Greece. The tremblor shook Izmir, Turkey, where it severely damaged 20 buildings. As of Monday, the death toll reached 91, including two teenagers in Greece, reports Al Jazeera.
Greece and western Turkey sit above a complicated convergence of chunks of Earth’s crust called tectonic plates. Four plates meet under the Aegean Sea, putting immense pressure on the plate directly below Turkey, Maya Wei-Haas reports for National Geographic. That makes the region one of the most geologically active in the world. It’s seen at least 29 earthquakes with magnitudes above 6.0 in the last century, Jariel Arvin reports for Vox. Last week’s earthquake has caused more than 900 aftershocks, 42 of which had a magnitude above 4.0, Isil Jariyuce and Maija Ehlinger report for CNN.
The complex geology of the region makes it difficult to study and predict its hazards, University of Leeds earthquake researcher Laura Gregory tells National Geographic. "There isn't one big fault that we can focus on, but instead many faults located over a huge area, most of which could cause a devastating earthquake," like the one on October 30, says Gregory through direct messages to National Geographic on Twitter.
When two massive slabs of Earth’s crust push, pull or slide against each other suddenly, earthquakes shake the surface. Modern buildings in earthquake-prone areas make use of construction techniques like base isolation to prepare for the natural disasters. In base isolation, the floor of a building is separated from its foundation, connected by strong but flexible isolators that allow the ground to shift underneath while the building wobbles above. But Izmir has many older buildings that aren’t equipped for quakes, the New York Times reports.
Turkey’s last earthquake of this scale happened in January, when a magnitude-6.8 earthquake killed more than 30 people in the eastern Elazig and Malatya provinces, BBC News reported at the time.
The region is so active because a trio of colliding plates are squeezing the Anatolian plate westward, almost like it “is being pushed out like a watermelon seed between two fingers,” University of Texas at Dallas tectonics expert Robert Stern tells National Geographic. At the same time, the African plate is diving below the western half of the Anatolian plate. That creates “slab suction,” University of Lisbon marine geologist Joao Duarte tells National Geographic. As one plate dips into the mantle, it drags everything above it along for the ride.
Friday’s earthquake was also followed by a small tsunami, per Vox, that flooded the streets of Izmir’s Seferihisar district.
Rescue teams are still searching for survivors in the rubble. One man, Oguz Demirkapi, was rescued after spending 30 minutes under 12 feet of debris, per the Times. He was in his third-floor apartment when the earthquake started, and he survived by curling up in a corner of the room while the building crumbled. Teams have also rescued a 70-year-old man after 34 hours under rubble, a three-year-old girl after more than 60 hours.
Murat Boz, who leads a civilian search and rescue team, tells the New York Times that rescue efforts would continue “nonstop, without a break, for 24 hours, day and night.”
Boz added, “We have experienced survival at the 187th hour of a previous earthquake. So if we take that as a benchmark, we are at the very beginning.”