A 4.1-magnitude earthquake in Yalova, a province south of Istanbul, sparked fears of the "big one" expected to hit Istanbul in the coming decades.

No casualties or damage to buildings were reported in the quake that was followed by a series of lesser aftershocks. Still, it was strong enough to remind Yalova residents of the 7.4-magnitude earthquake in 1999 that killed thousands in the region and devastated Yalova.

Experts played down the risk of a large magnitude earthquake for Istanbul, which is divided by the Marmara Sea with Yalova though they warned for a big earthquake in the immediate vicinity of Yalova.

The epicenter of the earthquake that took place at 5:36 a.m. was Çınarcık, a sleepy coastal town popular among pensioners. The epicenter was at a depth of 14 kilometers below the surface. Tremors were felt as far as Istanbul, Bursa which neighbors Yalova as well as Kocaeli, a province north of Yalova, which also suffered heavily from 1999 earthquake. Professor Ahmet Ercan, a seismology expert, told Demirören News Agency that the earthquake "had nothing to do" with the anticipated Istanbul earthquake, adding that it was "only a warning" for the region."An earthquake bigger in magnitude, at 6.3 or 6.4, is actually expected for the Cape of Armutlu, İmralı island and Gemlik Bay," he said, referring to a cape in Yalova, the Marmara Sea island which is home to a prison and a bay where a busy commercial port is located in the province of Bursa. "Such an earthquake will affect Bursa, Balıkesir, a province neighboring Bursa, and certainly Yalova," Ercan said. Oğuz Gündoğdu from the Geophysics Department of Istanbul University said that it indicated that breaking of a fault line that partially cracked in the 1999 earthquake, apparently continued.