Istanbul districts close to the Marmara Sea are at higher risk of earthquakes, an expert warns. Associate professor Bülent Özmen of Gazi University says Turkey's most populated city saw changes in terms of risk after an update of an earthquake risk map dating back to 1996. That risk map was published three years before a 7.4 magnitude earthquake hit the country's Marmara region where Istanbul is located and killed thousands of people. Özmen says the updated map was published in January and illustrated an increased earthquake risk for Istanbul, which is located near the sea, along with changes of the risk factors in other cities like the capital Ankara. "The new map also brought changes in classification of risk and now, every neighborhood, every settlement is categorized differently depending on their proximity to fault lines," he told Anadolu Agency (AA). Özmen says the new update also removed the description of risk areas as "primary earthquake zone or secondary earthquake zone" and was more specific. "Thanks to an e-government website, you can pinpoint coordinates of any given areas or even a single building and find out if it is at risk," he points out.
The update also changed the probability of earthquakes for cities, decreasing the risk for some and increasing it for others. "We see a higher risk of earthquakes in some Istanbul districts, but the new map allows us to pinpoint the exact location instead of declaring a risk for an entire district. The old map had Adalar [Prince's Islands], Avcılar, Bakırköy, Eminönü, Kadıköy, Kartal, Küçükçekmece, Maltepe, Pendik, Sultanbeyli, Tuzla, Üsküdar and Zeytinburnu as ‘primary earthquake areas,' but the new map shows variations for specific places of districts to exposure to earthquakes. So, instead of the risk for an entire district, we see neighborhoods closer to the sea are at higher risk." The map focuses on "ground acceleration" values now, and it also points to the increase in these values in areas previously designated as secondary risk areas. "The highest change is in Büyükçekmece with 70%, and it also variedly increased in neighborhoods nearer to sea in districts like Bağcılar, Bahçelievler, Esenler, Fatih and Güngören," Özmen says.
In the capital Ankara, earthquake risks also changed. Özmen says earthquake risk increased in central locations of the capital, while it decreased for previously dangerous areas like Evren, Şereflikoçhisar, Bala, Beypazarı, Çamlıdere, Elmadağ, Güdül, Kahramankazan and Kızılcahamam.