Eltanin fault system

The Eltanin fault system (Eltanin fracture zone) is a series of six or seven dextral transform faults that offset the Pacific-Antarctic Ridge, a spreading zone between the Pacific plate and the Antarctic plate. This is extending by up to 7.93 cm/year (3.12 in/year).^[1] It was named after the oceanographic ship USNS Eltanin.^[2]

Approximate surface projection on Southern Ocean of Eltanin fault system components (violet). Other nearby fracture zones (orange) and associated features such as probable extension of fracture zones are also shown (lighter orange). Click to expand map to obtain interactive fracture zone details.

Pacific Ocean depth map showing the Heezen fault and the Tharp fault as #17.

Description

The affected zone of the Pacific-Antarctic Ridge is about 800 km (500 mi) long, between 56° S, 145° W and 54.5° S, 118.5° W,^[3] southwest of Easter Island, and about as far as one can get from land on planet Earth (48°52.6′S 123°23.6′W).^[4] However, the total offset is about 1600 km.^[3] The two major faults in the Eltanin fracture zone are the Heezen transform fault and the Tharp transform fault, usually known as fracture zones as they extend inactively from the Pacific-Antarctic Ridge.^[2] A third named after Hollister, which is the shortest to the south, also exists and its active transform region has been linked to the other transform regions of the Eltanin fault system.^[2] They are about 1,000 km (620 mi) long and have been in the last 50 years the location of many earthquakes of up to M_w6.4.^[5] One segment of the Heezen transform has ruptured with an average repeat interval of 4 years.^[2] Others related faults include the Vacquier transform fault, the Menard transform fault, and the Udintsev fault.^[6]

To the northwest, in an almost linear fashion as seafloor features, are the Hollister Ridge and the Louisville Seamount Chain.

See also

• Hollister Ridge