The eastern Mediterranean Sea is a region of dynamic plate interactions involving the Eurasian and Aftican plates—dominated by the North Anatolian Fault and Hellenic subduction zone.

[1] The east Aegean Sea is a region of extensional tectonics; around Kos, this tectonic setting formed the Kos and Gökova grabens, Quaternary submarine structures trending northeast–southwest and east–west, respectively.

[2] Prior to 1933, Kos was damaged by an intermediate-depth (115 km (71 mi)) Ms  7.4 earthquake.

The April 1933 earthquake had magnitudes between 6.43 and 6.70; the International Seismological Centre cataloged it at Mw  6.4.

[3] The Modified Mercalli intensity on Kos ranged from VIII (Severe) to X (Extreme).

[4] In Kos historic city center, 90 percent of homes were demolished and only some government buildings were intact.

A newspaper reported ebb tide at Kos port for several tens of meters although it is unclear when did it occur.