Authorities said 35 people were injured, mostly in the panic that ensued after the quake.
A magnitude 6.0 earthquake has struck western Turkey, the European-Mediterranean Seismological Centre (EMSC) said, while the country’s interior minister said there were no immediate reports of deaths or significant damage.
The quake was at a depth of 2 kilometres (1.2 miles), EMSC said.
Turkey’s Disaster and Emergency Management Authority (AFAD), which measured the quake at magnitude 5.9, said the epicentre of the tremor had been in Golyaka, a district in the northwestern province of Duzce.
“We almost completed our checks in the villages around Golyaka. There is no severe damage reported; only some barns were wrecked in these places … There was a power cut during the quake but authorities are reinstating power now,” interior minister Suleyman Soylu said on broadcaster TRT Haber.
Health minister Fahrettin Koca said on Twitter that 35 people in Duzce and nearby provinces had been injured.
AFAD and media reports later updated the number of injured to 50.
Most of the injuries were sustained during the panic after the quake, including from jumping from balconies or windows. One of the injured was in a serious condition, Soylu said.
The quake struck at 4:08am (01:08 GMT) and Turkish media said it was also felt in Istanbul and the capital, Ankara.
Dozens of aftershocks were reported, including one of a magnitude 4.3.
The quake demolished the exterior cladding and parts of the roof of a courthouse in Duzce, Haberturk television reported. Among other damage, a two-storey shop collapsed on a narrow street, it said.
In Golkaya, people gathered in a main square, some wrapped in blankets distributed by the emergency management agency, television footage showed.
About 800 people were killed in a powerful earthquake that hit Duzce on November 12, 1999. In August of that year, 17,000 people were killed by another powerful temblor that devastated nearby Kocaeli province and other parts of northwest Turkey.
Officials said about 80 percent of the buildings in the area were rebuilt or fortified following the 1999 earthquakes, which helped minimise damage.
Turkey sits on top of major fault lines and is frequently shaken by earthquakes.