On October 30, when a powerful magnitude 7.0 earthquake struck under the Aegean Sea, dozens of buildings collapsed and water rushed into the streets of the coastal city of Izmir, Turkey, and on the island of Samos, Greece. At least 14 people have died and more than 400 were injured.
This region is no stranger to earthquakes, with a written record of tectonic destruction stretching back centuries. But while many earthquake-prone places around the world can trace their seismic activity to the meeting of just two main tectonic plates, the situation is far messier around the Aegean. The source of all the shaking is instead a complicated geologic jigsaw that makes up the area, cut through with a web of faults.
The reason this region is stretching apart like this “is highly debated," There is likely some combination of three main forces behind the extension,
One source comes from the watermelon seed effect, which causes "Tectonics Escape." As the larger Arabian and Eurasian plates shift around the Anatolian plate, the crustal rock gets shoved and squeezed.
Another major source of stretching is known as slab rollback, which occurs when one tectonic plate curls down under another and into the mantle. You can envision slab rollback by placing your left-hand flat on top of your right and slowly curling the fingers of your right hand—that's the slab dropping back and down into the deep.
This movement tugs at the overlying plate and the resulting stretching is called "slab suction". The underlying plate essentially sucks at the surface rocks. This process happens as the African plate dives under the western half of the Anatolian plate, under the Aegean Sea.
Another likely force at play could be a fairly simple one: Gravity. The center of the Anatolian plate is thick, which means "everything wants to kind of sink down and expand around the edges".
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