2003 Fiordland earthquake

Earthquake in New Zealand

2003 Fiordland earthquake

UTC time| 2003-08-21 12:12:49
ISC event| 7066570
USGS-ANSS| ComCat
Local date| 22 August 2003 (2003-08-22)
Local time| 12:12 AM
Magnitude| 7.2 Ms
Depth| 12 km (7.5 mi)
Epicentre| 45°06′14″S 167°08′38″E﻿ / ﻿45.104°S 167.144°E﻿ / -45.104; 167.144
Areas affected| New Zealand, South Island
Max. intensity| MMI VIII (Severe)[1]
Casualties| None

The 2003 Fiordland earthquake struck the remote region of Fiordland in the South Island of New Zealand on 22 August 2003, at 12:12 am NZST. The epicentre was 12 kilometres (7.5 mi) deep, and was thought to be near Secretary Island at the entrance to Doubtful Sound. At 7.2 Ms 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. 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.[2][3]

In August 2004, there was another large earthquake of magnitude 7.1 Mw in Fiordland.[4] This was the same location as an earthquake of 6.7 Ms magnitude on 10 August 1993.[5]

## Earthquake

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The magnitude 7.2 earthquake occurred on 22 August 2003, with an epicentre near Secretary Island in Fiordland.[6][7] The largest shallow earthquake with a magnitude this high in New Zealand occurred 35 years prior.[7]

There were over 8,000 recorded aftershocks in the two months following the main earthquake.[8] Of these, 23 were at least magnitude five,[7] and the largest measured 6.1.[9]

## Damage

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The Earthquake Commission received about 3,000 damage claims, totalling $10.5 million.[8] Most of the earthquake damage occurred in the township of Te Anau,[8][10] with about 64% of residents experiencing damage, mostly minor.[10] Some 70 km to the south-east of the town, residents felt the quake strongly and items fell off shelves in shops and homes.[11] Damage was generally minor, with some chimneys in Te Anau to Manapouri 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.[12]

External image

Landslides in Fiordland

A team of geologists led by Ian Turnbull went to investigate and reported "landsliding on a large scale". They recorded at least 200 landslides after overflying seventy percent of central and western Fiordland.[2] GNS Science recorded at least 400 landslides by November 2003.[13]

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.[14]

The earthquake also caused liquefaction in several places, such as on the coast of Lake Te Anau. Compared to other large New Zealand earthquakes, the liquefaction was minor.[15]

## Response

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Within 48 hours of the earthquake, two portable seismographs had been placed near the epicentre to record aftershocks. More portable seismographs were later used.[9]

## See also

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* 2009 Dusky Sound earthquake
* List of earthquakes in 2003
* List of earthquakes in New Zealand

## Notes

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1. ^ "EXPO-CAT Earthquake Catalog". Version 2007-12. United States Geological Survey. 1 December 2008. Retrieved 24 May 2025.
2. ^ a b Rogers 2013, p. 181,182.
3. ^ Wright 2014, p. 24.
4. ^ Wright 2014, p. 172.
5. ^ Hicks & Campbell 1998, p. 70.
6. ^ "Fiordland quake measures 7.8". New Zealand: Stuff. 23 July 2009. Retrieved 26 May 2024.
7. ^ a b c McGinty, Peter; Robinson, Russell (2007). "The 2003Mw7.2 Fiordland subduction earthquake, New Zealand: aftershock distribution, main shock fault plane and static stress changes on the overlying Alpine Fault". Geophysical Journal International. 169 (2): 579–592\. Bibcode:2007GeoJI.169..579M. doi:10.1111/j.1365-246x.2007.03336.x. ISSN 0956-540X.
8. ^ a b c "Geologists to keep watch after big quake". Otago Daily Times. 16 July 2009. Retrieved 25 May 2024.
9. ^ a b McGinty, P. (2004). "The 2003, MW 7.2 Fiordland Earthquake, and its nearsource aftershock strong motion data" (PDF). New Zealand Society for Earthquake Engineering. Retrieved 26 May 2024.
10. ^ a b "Analysis of Te Anau residents' impacts, awareness & preparedness following the 2003 Fiordland earthquake » EQC Toka Tū Ake". eqc.govt.nz. Retrieved 26 May 2024.
11. ^ "M 7.2 Fiordland Fri, Aug 22 2003". GeoNet. Retrieved 2 March 2024.
12. ^ Hancox et al. 2003, p. 23-25.
13. ^ Hancox et al. 2003, p. 1.
14. ^ "GeoNet M 7.2 Fiordland Fri, Aug 22 2003". GeoNet. Retrieved 26 May 2024.
15. ^ Hancox et al. 2003, p. 20-23.

## References

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* Hancox, G.T.; Cox, S.C.; Turnbull, I.M.; Crozier, M.J. (November 2003). Reconnaissance studies of landslides and other ground damage caused by the MW7.2 Fiordland earthquake of 22 August 2003 (PDF) (Report). GeoNet. Retrieved 26 May 2024.
* Hicks, Geoff; Campbell, Hamish (1998). Awesome Forces: The Natural Hazards that threaten New Zealand. Wellington: Te Papa Press. ISBN 978-0-909010-58-4.
* Rogers, Anna (2013) [1996]. The Shaky Isles: New Zealand Earthquakes (2 ed.). Wellington: Grantham House. pp. 181, 182. ISBN 978-1-86934-119-0.
* Wright, Matthew (2014). Living on shaky ground: The science and story behind New Zealand's earthquakes. Auckland: Random House (New Zealand). p. 172\. ISBN 978-1-77553-688-8.

## External links

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* The International Seismological Centre has a bibliography and/or authoritative data for this event.

* v
* t
* e

← Earthquakes in 2003 →

January|

* Colima (7.5, Jan 21)

February|

* Bachu (6.3, Feb 24) †

April|

* Alabama (4.6, Apr 29)

May|

* Bingöl (6.4, May 1) †
* Boumerdès (6.8, May 21) †
* Miyagi (7.1, May 26)

July|

* Dayao (5.9, July 21)
* Miyagi (6.4, July 26)

August|

* Fiordland (7.2, Aug 22)

September|

* Dominican Republic (6.4, Sep 22)
* Hokkaidō (8.3, Sep 25)
* Altai Republic (7.3, Sep 27)

December|

* Kazakhstan-China (6.1, Dec 1)
* Taiwan (6.8, Dec 10)
* San Simeon (6.6, Dec 22)
* Puerto Armuelles (6.5, Dec 25)
* Bam (6.6, Dec 26) † ‡

† earthquakes resulting in at least 30 deaths
‡ the deadliest earthquake of the year

* v
* t
* e

Earthquakes in New Zealand

Pre-colonisation|

* 1100 Alpine Fault
* 1460 Wellington
* 1600s Alpine Fault
* 1717 Alpine Fault
* 1815 New Plymouth
* 1817 Fiordland
* 1826 Fiordland
* 1835 Auckland
* 1838 Waitotara Forest

19th century|

* 1843 Wanganui†
* 1848 Marlborough†
* 1855 Wairarapa†
* 1863 Hawke's Bay
* 1868 Cape Farewell
* 1869 Christchurch
* 1888 North Canterbury†
* 1891 Port Waikato

20th century|

* 1901 Cheviot†
* 1904 Cape Turnagain†
* 1914 East Cape†
* 1921 Kaweka Forest
* 1929 Arthur's Pass
* 1929 Murchison†
* 1931 Hawke's Bay†
* 1934 Pahiatua†
* June 1942 Wairarapa†
* August 1942 Wairarapa
* 1947 Gisborne
* 1968 Inangahua†
* 1986 Raoul Island
* 1987 Edgecumbe

21st century|

* 2003 Fiordland
* 2004 Tasman Sea
* 2007 Gisborne
* 2009 Dusky Sound
* 2010 Canterbury
* 2010 Boxing Day
* February 2011 Christchurch†
* June 2011 Christchurch†
* December 2011 Christchurch†
* 2013 Seddon
* 2013 Lake Grassmere
* 2014 Eketāhuna
* 2016 Christchurch
* 2016 Te Araroa
* 2016 Kaikōura†
* 2021 Kermadec Islands

Related articles|

* Canterbury Earthquake Recovery Act 2011
* Canterbury Earthquake Response and Recovery Act 2010
* GeoNet
* Natural Hazards Commission

* † indicates earthquake known to have resulted in fatalities

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