Tsunamis bring Japan or the Indian Ocean to mind. Yet Türkiye’s coasts have seen tsunamis and will again. The catalogue of tsunamis affecting the Turkish coasts (Altınok and colleagues, 2011) lists 134 events in the last 3,500 years, 76 of them rated “probable” or “definite”. The good news: protecting yourself is simple, and it comes down to a few minutes of the right action.

What happened before

Marmara, 10 September 1509. According to the catalogue’s records for this earthquake, waves overtopped the walls in Galata and flooded Yenikapı and Aksaray, and the shipyard in İzmit collapsed. Finds from the Yenikapı excavations suggest the water may have reached 500–600 metres inland along the old Lycus (Bayrampaşa) stream valley.

Marmara, 17 August 1999. The Kocaeli earthquake also generated a tsunami in İzmit Bay. Field observations at 35 localities showed run-up of 1 to 2.5 metres along the shore. On the south coast, coastal landslides and subsided areas made the effects more complex (Altınok and colleagues, 2001).

Aegean, 20 July 2017. The Bodrum–Kos earthquake (Mw 6.6) caused a moderate tsunami with run-up of up to 1.9 metres. The Bodrum tide gauge recorded a wave 34 cm from trough to crest (Heidarzadeh and colleagues, 2017).

Aegean, 30 October 2020. The Mw 7.0 earthquake off Samos produced the largest tsunami in the Aegean since 1956 (Triantafyllou and colleagues, 2021). On the İzmir coast the highest run-up, 3.8 metres, was measured at Akarca; the worst damage was in Kaleiçi, Sığacık (Doğan and colleagues, 2021).

Eastern Mediterranean, 21 July 365. According to historical accounts, a great earthquake and tsunami off Crete devastated coastal cities from the Nile Delta to today’s Dubrovnik. Shaw and colleagues (2008) estimate that such tsunami-generating earthquakes may occur about once every 800 years along the Hellenic arc.

Why minutes matter

Most tsunamis around Türkiye are near-source: the earthquake is close to the coast, and so the wave arrives quickly. In the 2020 Samos tsunami, at a site about 12 km from the epicentre the sea withdrew 2 minutes after the earthquake and the largest wave arrived after 4 minutes (Triantafyllou and colleagues, 2021).

In Türkiye, tsunami monitoring is run by Kandilli Observatory’s Regional Earthquake and Tsunami Monitoring Center (KOERI-RETMC), one of the warning providers in UNESCO’s Intergovernmental Oceanographic Commission tsunami warning system for the North-eastern Atlantic and the Mediterranean (NEAMTWS). Still, after the 2017 Bodrum–Kos earthquake the warning centres in the region sent their messages 10 to 19 minutes after the earthquake; Kandilli’s came at 19 minutes. The researchers point out that even a 10-minute warning may not be enough for a near-source tsunami (Heidarzadeh and colleagues, 2017).

So at the coast, the fastest warning you will get is nature itself.

Natural warning signs

The US National Weather Service (NWS) says that if you are at the coast or in a low-lying area and notice any of the following, a tsunami could arrive within minutes:

  • A strong or long earthquake.
  • The sea acting strangely: looking like a fast-rising flood or a wall of water, or suddenly draining away and exposing the sea floor.
  • A loud roar from the ocean.

What to do at the coast

  1. Protect yourself first. During the shaking, drop, cover and hold on.
  2. Leave the shore as soon as the shaking stops. Do not wait for an official warning or instructions from officials. Go to high ground or as far inland as you can.
  3. Do not go to look at the receding sea. An exposed sea floor is a tsunami sign, not a sight to visit.
  4. Do not go back quickly. According to the NWS, the first wave may not be the largest or the last, and the danger can last hours or even days. In 2020, two inundations reached Vathy Bay on Samos about 19 minutes apart, and the second was stronger (Triantafyllou and colleagues, 2021). Stay away from the shore until officials say it is safe.

If you live at or holiday on the coast, pick a high point you can reach on foot from your home or hotel in advance, and add it to your family plan. If the designated assembly areas near you are on low ground by the sea, go uphill first after strong shaking.

Tsunamis are rare, but when they come, they come fast. The rule is simple: strong shaking, a receding sea or a roar means go high.