Alpine Fault
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 Mw8.1± 0.1. The probability of another one occurring before 2068 was estimated at 75 percent in 2021.
| Alpine Fault | |
|---|---|
Movement along the Alpine Fault is deforming the continent of Zealandia, with the southern part (on the Pacific Plate) sliding past and slightly onto the northwest part (on the Australian Plate). | |
| Etymology | Southern Alps |
| Country | New Zealand |
| Region | West Coast and Southland Regions |
| Characteristics | |
| Range | Southern Alps |
| Length | 600 km (370 mi) |
| Strike | NE-SW |
| Displacement | 30 mm (1.2 in)/yr |
| Tectonics | |
| Plate | Australian, Pacific |
| Status | Active |
| Earthquakes | 1717 prehistoric |
| Type | Strike-slip fault |
| Movement | Up to Mw8.2, dextral/convergent, east side up |
| Age | Miocene-Holocene |
| Orogeny | Kaikoura |
| New Zealand geology database (includes faults) | |