Summary
The 2007 Gisborne earthquake occurred under the Pacific Ocean about 50 kilometres (31 mi) off the eastern coast of New Zealand's North Island at 8:55 pm NZDT on 20 December. The tremor had a moment magnitude of 6.7 and maximum Mercalli intensity of VII (Very Strong), and affected the city of Gisborne, but was felt widely across the country from Auckland in the north to Dunedin in the south.[1]
 Damage outside Health 2000 Main Street | |
  | |
| UTC time | 2007-12-20 07:55:15 |
|---|---|
| ISC event | 13293317 |
| USGS-ANSS | ComCat |
| Local date | 20 December 2007 |
| Local time | 8:55 pm NZDT (UTC+13) |
| Magnitude | 6.7 Mw[1] |
| Depth | 33 km (21 mi) |
| Epicentre | 38°53′S 178°32′E / 38.89°S 178.54°E |
| Areas affected | New Zealand |
| Max. intensity | MMI VII (Very strong) |
| Peak acceleration | 0.28 g |
| Casualties | 1 dead, 11 injured |
Tectonic setting edit
New Zealand lies along the boundary between the Australian and Pacific plates.
- In the South Island, most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, the Alpine Fault.
- In the North Island, displacement is mainly taken up along the Kermadec-Tonga subduction zone, although the remaining dextral strike-slip component is accommodated by the North Island Fault System. Subduction off the coast takes place at the Hikurangi Trench, which runs parallel to the East Coast of the North Island and is the southern extension from the Kermadec Trench, however earthquakes here occur less frequently.[2]
Effects edit
While the earthquake was initially reported to have caused no deaths, an elderly woman in Gisborne suffered a heart attack and died shortly after the quake.[3] A number of buildings in central Gisborne were damaged. The central business district was closed off to allow building inspectors to assess buildings for damage; three buildings had collapsed. There were blackouts immediately after the earthquake hit.[4] The town clock stopped at 8:55 pm.[5] As of 14 January 2008, the Earthquake Commission had received over 3100 insurance claims amounting to $16 million.[6] It was earlier estimated that the cost of damage caused by the earthquake could rise to $30 million.[7]
See also edit
References edit
- ^ a b M 6.7, Gisborne, 20 December 2007. GeoNet.
- ^ Mouslopoulou, V., Nicol, A., Little, T. A., & Walsh, J. J. (2007). Terminations of large strike-slip faults: an alternative model from New Zealand. Geological Society, London, Special Publications, 290 (1), pp 387–415.
- ^ One dead, up to 20 injured after huge quake, The New Zealand Herald, 21 December 2007.
- ^ Quake 6.8 magnitude hits east coast, TVNZ, 21 December 2007.
- ^ 'Rattled Gisborne residents pick up the pieces after quake', 3News. 21 December 2007. Retrieved 6 June 2009. Archived 10 June 2009.
- ^ Recent events Archived 26 February 2008 at the Wayback Machine, EQC Insurance. Updated and. Retrieved 14 January 2008.
- ^ The $30m shockwave Archived 23 December 2007 at the Wayback Machine, 22 December 2007
External links edit
- New Zealand earthquake report – Magnitude 6.7, Thursday, 20 December 2007 at 8:55:17 pm (NZDT). GeoNet.
- M 6.6 – off the east coast of the North Island of New Zealand (U.S. Geological Survey)
- The International Seismological Centre has a bibliography and/or authoritative data for this event.