Greece and Turkey Shaken by African Tectonic Retreat

by Ozan Sinoplu

On October 30, 2020, there was a devastating magnitude 7.0 offshore earthquake between Samos Island (Greece) and Izmir (Turkey) . Initial rupture happened between 11- 21 km below the surface of the Earth, and the quake left 118 deaths and multiple collapsed and damaged buildings behind.

Earthquakes are a consequence of the motions of the planet’s tectonic plates. When tectonic plates move around, they interact with others and when two large land masses interact, it results in deformation on both plates. Sometimes this deformation concentrates on the edges, and sometimes it is accompanied by internal deformation of the plates. Ultimately, this deformation generally manifests itself in the form of earthquakes, tsunamis, and volcanism.

The Aegean Region (Eastern Greece and Western Turkey) is one of the most historically rich areas around the world. The area has numerous ancient cities and archeological sites, most of which date back over hundreds of years. In Greek mythology, the area was said to be frequently visited by Poseidon, the Greek god of the sea, earthquakes, and horses. Geologically, this region is one of the most active areas of tectonic movement on the planet, which has resulted in numerous ancient cities being destroyed by earthquakes. Despite this, Aegean civilizations have consistently repaired the damage and continued living there. One cannot keep oneself from wondering; Why not find a better place with fewer earthquakes? The answer might have something to do with nice beaches and good wine, but that’s beyond the scope of this article.

Fig.1:Simplified model of active tectonics in Anatolia.

Frequent tectonic activity in the Aegean region brings lots of natural resources to the area, but it also causes many hazards. As can be seen in Figure 1, the Arabian plate is moving northwards, colliding with the Eurasian Plate and the Anatolian Microplates along the East Anatolian Fault (EAF) and Bitlis-Zagros Collision Zone (BZCZ). This collision forces the Anatolian Plate to escape to the west along the North Anatolian Fault (NAF), causing the West Anatolian Extensional Province (WAEP) to extend to the north and the south.

This tectonic action in the region results in intense earthquake activity and a volcanic belt known as the South Aegean Volcanic Arc , which includes some historically active volcanoes, such as Methana volcano at the western edge of the volcanic arc, Milos and Santorini volcanos in the central part, and Nisyros and Kos at the eastern edge near the Turkish coast (Fig. 2). Volcanoes in this arc have caused some of the most tremendous and significant catastrophes in human history.

Fig 2: Panel A: Map of the Aegean area. October 30, 2020 Samos Earthquake epicenter is shown with the star. Panel B: A picture from Izmir after the earthquake.

A large number of ancient cites were built close to the aforementioned active fault zones and destroyed by strong historical earthquakes. For instance, the city of Priene (Fig. 2), one of the earliest Ionian settlements within the western Büyük Menderes Graben, was destroyed by an earthquake in 350 BCE and rebuilt 8 km away. The ancient city of Ephesus (Fig. 2), a Greek city on the coast of Ionia, was built in the 10th century BCE and destroyed by earthquakes several times, with the most recent destruction occurring in 17 CE.

Having a rich tectonic history and active tectonism results in many natural resources and landscape beauties. However, these resources come with a hazardous price. It is crucial to understand how nature works in order to mitigate these hazards and create a safe living environment for people. Readers who are interested in learning more about the topic are referred to our paper on Nature-Scientific Reports (Meng et al., 2021*).

Disclaimer: The views and opinions in this work are those of the author and do not necessarily reflect the views of Auburn University.