This happened near the town of Tepehan in Turkey. There are YouTube videos of it, and if you look at the satellite view of Tepehan on Google Maps, you see the landscape from before the quake. It's a tumultuous-looking place.

The DH, who is a geologist, thinks the canyon is a graben, a down-dropped block in a rift zone.   The big picture is that Africa and Arabia are being pushed northeastward into Europe, and there is subduction in the eastern Mediterranean area. Google "map of earth's plates with arrows showing movement."