According to the American Seismological Institute (USGS), the quake was recorded at 8:43 am local time (0043 GMT), at a depth of 10 km in the province of Abra, on the main island of Luzon.
In the town of Dolores, located very close to the epicenter, terrified residents ran from their homes and the windows of the local market were shattered, local police commander Edwin Sergio told AFP.
"The earthquake was very strong," Mr. Sergio said. "The fruit and vegetable tables in the market were knocked over," he continued, adding that cracks had appeared on the walls of the police station.
Another police commander, Nazareno Emia, told AFP that several injured people had been taken to hospital.
A video posted on Facebook and verified by AFP also showed cracks in an asphalt road and the ground in the town of Bangued, but no visible damage to shops or houses.
- Feel at 300 km -
Mira Zapata, a college student, said he was at his house in the city of San Juan when he felt "a very strong jolt".
"We started screaming and ran outside," he said, as the aftershocks continued. "Our house is in good condition but those down the hill were damaged," continued this witness.
Skyscrapers shook as far as the capital Manila, located more than 300 km to the south.
The Philippines is regularly hit by earthquakes due to its position on the "Ring of Fire", an arc of intense seismic activity that circles the Pacific Ocean through Japan and Southeast Asia.
Wednesday's earthquake is the most powerful in the country in years.
In October 2013, a magnitude 7.1 earthquake on the island of Bohol, in the center of the country, killed more than 200 people and displaced 400,000.
The tremor had triggered catastrophic landslides. Tens of thousands of homes as well as historic churches dating from the early days of Catholicism in the Philippines had been destroyed.
This powerful earthquake had changed the landscape of the island and caused a spectacular "break in the ground", causing a part of the ground to rise up to three meters and creating a wall of rock above the epicenter.
In 1990, a magnitude 7.8 earthquake in the northern Philippines killed more than 1,200 people, caused extensive damage in Manila and broke ground over more than a hundred kilometres.
