When Plates Collide
January 30, 2001
What happens to bedrock where two continental plates slide past each other? The sliding surface is crushed and ground into loosely aggregated rock called fault gouge. This is an exposure along the North Anatolian Fault zone in northwestern Turkey a few hundred kilometers east of the location of the devasting magnitude 7.4 Kocaeli (Izzmit) earthquake of 1999. The naturally crushed fault gouge (the light colored rock) is being quarried here as raw material for concrete and road building.