CLIPPERTON FRACTURE ZONE

fracture zone in the Earth's surface, in the floor of the northeastern equatorial Pacific Ocean, discovered and delineated by expeditions of the Scripps Institution of Oceanography in 1950 and succeeding years. The fracture zone is more than 7,240 km (4,500 miles) long, trending east-northeast along a global small circle from the vicinity of the Line Islands at about latitude 2 N and longitude 153 E to the vicinity of the Middle America Trench off Central America at latitude 10 N. The Clipperton Fracture Zone is one of a family of five great lineations in the North Pacific seafloor, all of which conform closely to global small circles concentric about a common pole at latitude 79 N and longitude 111 E. This geometry suggests a common history for the fracture zones and implies that the Clipperton Fracture Zone, like its northern counterparts, was produced as a scar of transform faulting associated with seafloor spreading that began at least 80 million years ago. See also seafloor spreading hypothesis.