Turkey earthquake: The eyewitnesses who captured the quake on social media

The sheer scale of the devastation of the earthquake and its aftershocks can be seen in social media photos and videos posted by people in Turkey and Syria. Eyewitnesses have also been speaking about what happened. BBC News has been pulling together and verifying information.

The tremors of the main quake - which happened at 04:17 local time - were felt more than a hundred miles in each direction from the epicentre - across southern Turkey and in northern Syria.

Witnesses described being shaken from their sleep and running to their cars for safety from the damaged buildings.

"I have never felt anything like it in the 40 years I've lived," said Erdem, living in the city of Gaziantep. "We were shaken at least three times very strongly, like a baby in a crib."

BBC News has been piecing together what happened as the tremors struck and reverberated across Turkey and Syria - using personal testimony and social media posts which we have verified.

In one verified tweet a camera pans across smoke-filled scenes of rubble and destruction in Iskenderun, southern Turkey.

BBC Turkish spoke to earthquake survivors from different cities - all of them said it was the first time they had experienced such severe and long-lasting tremors.

Hundreds of buildings are reported to have been destroyed in the Pazarcık district of Kahramanmaraş, to the north of the epicentre.

Footage on Twitter shows an aerial view of the force of the quake in the city's palm tree-lined streets.

One local resident Veysel Şervan told the BBC that many of his relatives were under the rubble.

"I barely got myself and my family out of the building. We were just coming out of the wreckage when we saw a person reach out through a small gap. The building collapsed on our friend who tried to save them. They have no chance of escape, it collapsed on them completely. We are in a very difficult situation."

Videos have emerged showing large fires in southern Turkey, with people claiming the earthquake has caused gas pipelines to burst and burn out of control.

The BBC has verified one of the videos as being on the outskirts of the city of Hatay, around 170km from the earthquake epicentre.

A still from drone footage taken over Hatay shows numerous apartment buildings collapsed in one neighbourhood.

The tremors caused this hospital in the city to collapse at an angle.

Gaziantep resident Russell Peagram, from Essex, described efforts to help elderly neighbours escape from apartment buildings in freezing temperatures.

"Neighbours got together, it was teamwork. If there was an old lady or an old man who'd come down and you had space in your car, everyone was just getting blankets and sharing them, whatever they could do."

The earthquake reduced the city's castle and the Shirvan Mosque to rubble. Gaziantep castle had been one of the country's best-preserved castles dating back to the Roman period.

Aftershocks to the east and south of the initial epicentre - including a significant second quake - have been felt since.

Here Turkish TV captured the moment the second earthquake struck in the city of Malatya.

In Sanliurfa, an eyewitness captured the moment a building collapsed in the Bahçelievler neighbourhood.

BBC journalists were able to confirm the location was in Sanilurfa - rather than, according to an earlier social media claim, Aleppo in Syria.

We used geolocation tools and checked individual thumbnails from the video to see when it was first posted.

While in Gaziantep, this moment was captured on video - when it became clear that another building was about to collapse.

Across the border in northern Syria, the situation is just as desperate.

One resident in Azaz, a city in north-west Syria, told the media how frightening the situation had been.

"There are 12 families [trapped here] and no-one managed to get out."

In the city of Aleppo, a woman holding a small child, ran as buildings fell in quick succession.

While in the village of Besnaya-Bseineh, near Harim, before and after images show homes have been flattened - and how the search is on for survivors.

Verification and additional reporting: Richard Irvine-Brown, Paul Myers, Olga Smirnova, Daniele Palumbo, Tom Spencer, Joshua Cheetham, Shayan Sardarizadeh, Rozina Sini