The North Anatolian fault stretches across northern Turkey and its movement is strike-slip in nature just like the ancient movement seen at the Great Glen Fault in Scotland. The fault runs along the boundary between the Eurasian plate and the smaller Anatolian plate but movement in the area is controlled by collision of the larger Arabian plate to the south and the Eurasian plate to the north. The fault is a transform fault with the Anatolian Plate and the Eurasian Plate sliding past each other 

	Building damage from the Duzce earthquake: © Halit Edip Özcan

The fault is 1500 kilometres long and stretches from the junction with the East Anatolian fault in eastern Turkey all the way across northern Turkey and into the Aegean Sea. Most concerning for earthquake geologists is that it passes within 20km of Istanbul; the most populated city in Turkey. 

This fault has been the site of a number of disastrous earthquakes including the 1939 Erzincan earthquake which resulted in the death of more than 32,000 people and injured more than 100,000. Since then, there have been seven further earthquakes measuring over 7.0 in magnitude including the7.6-magnitude Golcuk-Kocaeli earthquake which directly struck the city of Izmit in 1999, killing over 17,100 people, and displacing 250,000 others.  

Regional plate tectonics: © Molear 3

Seismologists think that earthquakes are progressing along the fault from west to east with each one triggering the next further west along the fault.  Over the past century earthquake events have been moving in a broadly westerly direction and this create significant concern around the potential for a major earthquake in the vicinity of Istanbul, a city with a population of more than 14 million people, which was also suffered heavy damage in the 1999 earthquake despite being 110km away from the epicentre.