Although ancient earthquakes did great damage, none could compare with a 21st-century quake because Istanbul today is a city of more than 14 million people, many living, working and going to school in sub-standard buildings.
A technical study by the US Coast and Geodetic Survey puts the risk of a major earthquake in Istanbul during the next 30 years at 62%.
Many of the city's famed historical monuments such as Ayasofya (Hagia Sophia) and the Sultanahmet (Blue) Mosque may withstand the quake because they were designed by earthquake-aware architects and engineers, built soundly of quality materials, and...they've already survived several substantial earthquakes. In many cases, reinforcements have been added when damage from earlier quakes has been repaired.
But many modern buildings, especially smaller residential structures, were designed and built by people with little or no professional or technical training or knowledge.
Even some more substantial public and private buildings were designed with construction speed or profit, not earthquake survivability, in mind. In place of high-quality construction-grade sand and new steel, salt-laden beach sand and steel from scrap may have been used, leading to corrosion, weakening and ultimately collapse.
A city well prepared for earthquake maintains large open areas (parks, playing fields, cemeteries, etc.) that can be used as assembly and emergency treatment areas in the event of an earthquake. In Istanbul, many areas designated for earthquake relief have been built over. Shopping malls are no good in an earthquake.
What can you, as a visitor, do to protect yourself on a visit to Istanbul?
Earthquakes are by their nature sudden and unpredictable. It's all over within a minute or two, and you're left with the result. There are some things you can do. Crawling under a sturdy desk or table, huddling in a corner away from windows, moving from beneath lighting fixtures, standing beneath a sturdy load-bearing door lintel, running away from tall structures, trees, towers or anything that can fall on you may help to prevent immediate injury, but that's only the beginning of the problem.
Broken water, electric, gas and sewage lines leave the immense population without essential services but with perils from electrocution, explosion and disease. Fire-fighting becomes nearly impossible just when it's needed most because streets are blocked by rubble and water mains have burst. Food and medical supplies are disrupted, policing is very difficult. Seismic waves may sweep across coastal areas.
For at least the first 72 hours, you may be on your own to supply all your needs for food, water, shelter, medical help and safety.
With such a threat, should you visit Istanbul?
That's something you must decide. As for me, I go to Istanbul all the time, and I will continue to go. Many places in the world face similar earthquake dangers, including Alaska, California, China, Guatemala, Italy, Iran, Japan, Mexico, Nepal, Pakistan, etc.
But we all face even greater dangers every day—heart disease, auto accidents—and think little of them. Look at these common risks and dangers....