West Coast, New Zealand

A coast (also called the coastline, shoreline, or seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, such as that caused by waves. The geological composition of rock and soil dictates the type of shore that is created. Earth has about 620,000 km (390,000 mi) of coastline.

Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor ecosystems, such as freshwater or estuarine wetlands, that are important for birds and other terrestrial animals. In wave-protected areas, coasts harbor salt marshes, mangroves, and seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic animals. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals (e.g. mussels, starfish, barnacles) and various kinds of seaweeds.

The Southern Alps (Māori: Kā Tiritiri o te Moana; officially Southern Alps / Kā Tiritiri o te Moana) are a mountain range extending along much of the length of New Zealand's South Island, reaching its greatest elevations near the range's western side. The name "Southern Alps" generally refers to the entire range, although separate names are given to many of the smaller ranges that form part of it.

The range includes the South Island's Main Divide, which separates the water catchments of the more heavily populated eastern side of the island from those on the west coast. Politically, the Main Divide forms the boundary between the Marlborough, Canterbury and Otago regions to the southeast and the Tasman and West Coast regions to the northwest.

The Alpine Fault is a geological fault that runs almost the entire length of New Zealand's South Island, being about 600 km (370 mi). long, and forms the boundary between the Pacific plate and the Australian plate. The Southern Alps have been uplifted on the fault over the last 12 million years in a series of earthquakes. However, most of the motion on the fault is strike-slip (side to side), with the Tasman district and West Coast moving north and Canterbury and Otago moving south. The average slip rates in the fault's central region are about 38 mm (1.5 in) a year, very fast by global standards. The last major earthquake on the Alpine Fault was in about 1717 AD with a great earthquake magnitude of M_w8.1± 0.1. The probability of another one occurring before 2068 was estimated at 75 percent in 2021.

Buller District is one of 53 districts of New Zealand, and is within the West Coast Region. It covers Westport, Karamea, Reefton and Inangahua Junction.

Buller District's overall land area is 7,943.35 km (3,066.94 sq mi). The district is administered by the Buller District Council with the seat in Westport, in which 45% of the district's population live.

Grey District is a district in the West Coast Region of New Zealand that covers Greymouth, Runanga, Blackball, Cobden, and settlements along the Grey River. It has a land area of 3,474.31 square kilometres (1,341.44 sq mi). The seat of the Grey District Council, the local government authority that administers the district, is at Greymouth, where 59.0% of the district's population live.

The Grey District is on the West Coast of the South Island. It stretches from the south banks of the Punakaiki River in the north, southeast to Mt Anderson, north to The Pinacle, southeast to Craigeburn, in a southeast direction to Mt Barron, southwest to Jacksons and following the Taramakau River to the Tasman Sea.