An earthquake on April 11 off the coast of the Black Sea renewed fears of a major disaster for Turkey’s northern region. Tremors felt as far as Istanbul were the result of a magnitude 4.4 earthquake with an epicenter in Ereğli in Zonguldak province, some 270 kilometers (168 miles) to the east. Professor Hasan Sözbilir, who heads an earthquake research center, says fault lines in the Black Sea have the potential to generate an earthquake at the magnitude of 7.0, a fairly devastating scale.

Turkey has always been on alert against earthquakes as a country crisscrossed with fault lines, especially after a 1999 earthquake that killed thousands of people in the northwest. The western parts of the Black Sea region have had their fair share of destruction and fatalities, with the 1999 earthquake off the Black Sea coast and another earthquake in Düzce, just a few months later, killing hundreds.

Sözbilir, who chairs the Center for Earthquake Research and Application at Izmir Dokuz Eylül University, said the recent earthquake stemmed from a northeast-southwest fault line running parallel to the western Black Sea region coast of Turkey. He told Demirören News Agency (DHA) on Wednesday that the Black Sea region was likely sandwiched between fault lines at sea and the Northern Anatolian fault line on land, which was the culprit of the 1999 earthquake.

"Active fault lines exist beneath the Black Sea and we last saw their activity in a 6.8-magnitude earthquake in Bartın (a Black Sea province) back in 1968. It is of vital importance to create a better map of the region to examine underwater fault lines and research their potential. We also need to find out the potential risk of tsunamis for cities across the region," he warned.

For professor Naci Görür, it is a matter of time rather than place to see another devastating earthquake, especially for Istanbul, Turkey’s most populated city. Görür, a geology expert, said the Ereğli earthquake is not related to fault lines straddling the Marmara region in the west, which also includes Istanbul. But he said the city was "running out of time" in the face of a potential earthquake at a magnitude of 7.0 or higher. "It is not very possible that the fault line that caused the earthquake on April 11 will trigger another earthquake for Istanbul."

Görür told DHA on Thursday that next major earthquakes would likely occur along the Eastern Anatolia fault line, in a region covering the provinces of Malatya and Kahramanmaraş.