The 2003 Fiordland earthquake struck the remote region of

Fiordland Fiordland (, "The Pit of Tattooing", and also translated as "the Shadowlands"), is a non-administrative geographical region of New Zealand in the south-western corner of the South Island, comprising the western third of Southland. Most of F ...

in the

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

on 22 August 2003, at 12:12 am

NZST Time in New Zealand is divided by law into two standard time zones. The main islands use New Zealand Standard Time (NZST), 12 hours in advance of Coordinated Universal Time (UTC) / military M (Mike), while the outlying Chatham Islands use C ...

. The epicentre was deep, and was thought to be near

Secretary Island Secretary Island () is an island in southwestern New Zealand, lying entirely within Fiordland National Park. Roughly triangular in shape, it lies between Doubtful Sound / Patea in the south and Te Awa-o-Tū / Thompson Sound in the north, with ...

at the entrance to

Doubtful Sound Doubtful Sound / Patea is a fiord in Fiordland, in the far south west of New Zealand. It is located in the same region as the smaller but more famous and accessible Milford Sound / Piopiotahi. It took second place after Milford Sound as New Ze ...

. At 7.2 magnitude, it was one of the largest quakes in the country for some time, and was the largest shallow quake since the

1968 Inangahua earthquake Events January–February * January 1968, January – The I'm Backing Britain, I'm Backing Britain campaign starts spontaneously. * January 5 – Prague Spring: Alexander Dubček is chosen as leader of the Communist Party of Cze ...

. There was an aftershock two hours later at 2:12 am, followed over several days by frequent small tremors; two months after the earthquake, there had been 8,000 aftershocks. Fiordland is one of the seismically active parts of the country according to GNS seismologist Dr. Warwick Smith, as they are a relief mechanism for stresses as the Australian and Pacific tectonic plates are being forced together in the area, with the Pacific plate subducting under the Australian plate. In August 2004, there was another large earthquake of magnitude 7.1 in Fiordland. This was the same location as an earthquake of 6.7 magnitude on 10 August 1993.

Earthquake

The magnitude 7.2 earthquake occurred on 22 August 2003, with an epicentre near

. The largest shallow earthquake with a magnitude this high in New Zealand occurred 35 years prior. There were over 8,000 recorded aftershocks in the two months following the main earthquake. Of these, 23 were at least magnitude five, and the largest measured 6.1.

Damage

The

Earthquake Commission The Natural Hazards Commission – Toka Tū Ake is a New Zealand Crown entity that invests in natural disaster research and education and provides natural disaster insurance to residential property owners. It is a continuation of the Earthq ...

received about 3,000 damage claims, totalling $10.5 million. Most of the earthquake damage occurred in the township of

Te Anau Te Anau is a town in the Southland, New Zealand, Southland List of regions in New Zealand, region of the South Island of New Zealand. In Māori language, Māori, Te-Anau means the Place of the Swirling Waters. It is on the eastern shore of Lake ...

, with about 64% of residents experiencing damage, mostly minor. Some 70 km to the south-east of the town, residents felt the quake strongly and items fell off shelves in shops and homes. Damage was generally minor, with some chimneys in Te Anau to

Manapouri Manapouri is a small town in Southland / Fiordland, in the southwest corner of the South Island, in New Zealand. The township is the westernmost municipality in New Zealand. Located at the edge of the Fiordland National Park, on the eastern ...

being cracked or broken. The earthquake also caused some concrete to crack in the control structure of Lake Te Anau, and collapses in Kepler Track. A team of geologists led by Ian Turnbull went to investigate and reported "landsliding on a large scale". They recorded at least 200

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

s after overflying seventy percent of central and western Fiordland.

GNS Science GNS Science (), officially registered as the Institute of Geological and Nuclear Sciences Limited, is a New Zealand Crown Research Institute. It focuses on geology, geophysics (including seismology and volcanology), and nuclear science (partic ...

recorded at least 400 landslides by November 2003. There was also a tsunami, which occurred in two separate locations. One of them was caused by a landslide, had a run-length of 4–5 metres, and affected several hundred metres of Charles Sound and damaged a wharf. The other part was recorded as far Port Kembla, on the east coast of Australia, with a peak-to-trough height of 0.17 metres. The earthquake also caused

liquefaction In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of t ...

in several places, such as on the coast of

Lake Te Anau Lake Te Anau () is in the southwestern corner of the South Island of New Zealand. The lake covers an area of , making it the second-largest lake by surface area in New Zealand (after Lake Taupō) and the largest in the South Island. It is the ...

. Compared to other large New Zealand earthquakes, the liquefaction was minor.

Response

Within 48 hours of the earthquake, two portable

seismographs A seismometer is an instrument that responds to ground displacement and shaking such as caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The out ...

had been placed near the epicentre to record aftershocks. More portable seismographs were later used.

Notes

References

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External links