An earthquake was felt in Istanbul, with the tremor reported at 18:11 local time. The shaking sent residents to social media within minutes to describe how it felt where they were. Turkey's disaster and emergency authority, AFAD, has not yet published details on the epicenter or the quake's magnitude. That silence has left a gap between the widespread reports of a tremor and any official confirmation of its strength. People in Istanbul react sharply to any shake because the city sits close to the North Anatolian fault. Seismologists have warned for years that the region is overdue for a powerful quake. Residents are waiting on official readings before judging how serious this one was.