Hikurangi Trench

Map of the Zealandia continent.

The Hikurangi Trench (also called the Hikurangi Trough) is a linear feature in the bed of the Pacific Ocean off the east coast of the North Island of New Zealand, lying between the southern end of the Cook Strait and the Chatham Rise. Though much shallower, it is the southward continuation of the Kermadec Trench and forms part of the Kermadec-Tonga subduction zone. It represents the part of the subduction zone where the thick oceanic Hikurangi Plateau is subducting beneath continental crust of the Indo-Australian Plate. By contrast, the Kermadec and Tonga Trenches represent the parts of the subduction zone where oceanic crust of the Pacific Plate is subducting beneath oceanic crust of the Indo-Australian Plate.

Although shallower than the trenches north of it, the Hikurangi Trench reaches depths of 3,000 metres as close as 80 kilometres from shore. Its maximum depth is about 3,750 metres (12,300 ft).

At the southern end of the trench, off the coast of Marlborough, New Zealand, the seabed rises sharply, and because of the prevailing winds and tides in this area, many deep water species are found close to the shore. This food source attracts the whales for which the town of Kaikoura is famous.

The plate boundary continues inland along the Marlborough Fault System, linking through to the Alpine Fault. Here the plates converge much more obliquely, exhibiting transpression instead of subduction.

See also

• Oceanic trench
• Kaikoura Canyon

References

• Intraplate Volcanism in Eastern Australia and New Zealand, Stuart Ross Taylor, Robert Wallace Johnson, Jan Knutson, Australian Academy of Science, Cambridge University Press, 1989, ISBN 0-521-38083-9.