2010 Canterbury earthquake

2010 Canterbury earthquake

Christchurch Wellington
UTC time	2010-09-04 04:35:46
ISC event	15155483
USGS-ANSS	ComCat
Local date	4 September 2010 (2010-09-04)
Local time	04:35 NZST
Magnitude	7.1 Mw[1][2]
Depth	10 km (6.2 mi)[2]
Epicentre	43°33′S 172°11′E / 43.55°S 172.18°E / -43.55; 172.18 near Darfield, Canterbury
Areas affected	New Zealand
Max. intensity	MMI X (Extreme)[3]
Peak acceleration	1.26 g[4]
Aftershocks	~17,600 (as of early August 2016)[5]
Casualties	2 fatalities, 2 seriously injured, approximately 100 total injuries[6]

The 2010 Canterbury earthquake (also known as the Darfield earthquake)^[7] struck the South Island of New Zealand with a moment magnitude of 7.1^[1][2] at 4:35 am local time on 4 September, and had a maximum perceived intensity of X (Extreme) on the Mercalli intensity scale.^[1] Some damaging aftershocks followed the main event, the strongest of which was a magnitude 6.3 shock known as the Christchurch earthquake that occurred nearly six months later on 22 February 2011.^[8] Because this aftershock was centred very close to Christchurch, it was much more destructive and resulted in the deaths of 185 people.^[9]

The earthquake on 4 September caused widespread damage and several power outages, particularly in the city of Christchurch, New Zealand's second largest city at that time.^[6][10] Two residents were seriously injured, one by a collapsing chimney and a second by flying glass.^[6][11] One person died of a heart attack^[12] and another from a fall.^[13] Mass fatalities were avoided partly due to there being few houses of unreinforced construction, although this was also aided by the quake occurring during the early hours of the morning when most people were off the street.^[14][15]

The earthquake's epicentre was 40 kilometres (25 mi) west of Christchurch, close to the town of Darfield.^[16] The hypocentre was at a depth of 10 km.^[1] A foreshock of roughly magnitude 5.8 hit five seconds before the main quake,^[17] and strong aftershocks were reported,^[6][18] up to magnitude 5.4.^[19] The quake was felt as lasting up to 40 seconds,^[10] and was felt widely across the South Island, and in the North Island as far north as New Plymouth.^[20] As the epicentre was on land away from the coast, no tsunami occurred.^[16]

The National Crisis Management Centre in the basement of the Beehive in Wellington was activated, and Civil Defence declared a state of emergency for Christchurch, the Selwyn District, and the Waimakariri District, while Selwyn District, Waimakariri and Timaru activated their emergency operation centres.^[21] Initially, a curfew was established for parts of Christchurch Central City from 7 pm to 7 am in response to the earthquake. The New Zealand Army was deployed to the worst affected areas in Canterbury.^[11]

Insurance claims totalled between NZ$2.75 and $3.5 billion,^[22] although it is unclear how much cost can be attributed to each of the earthquake events in the 2010–2011 Canterbury earthquake sequence. The total estimated damage bill was up to $40 billion, making it the fifth-biggest insurance event in the world since 1953.^[23]