The 2013 Seddon earthquake measured 6.5 on the scale and was centred in New Zealand's

Cook Strait Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A H, ...

, around east of the town of Seddon in

Marlborough Marlborough may refer to: Places United Kingdom * Marlborough, Wiltshire, England ** Marlborough College, public school * Marlborough School, Woodstock in Oxfordshire, England * The Marlborough Science Academy in Hertfordshire, England Austral ...

. The earthquake struck at 5:09:30 pm on Sunday 21 July 2013 (05:09 UTC) at a depth of , according to

Geonet GeoNet was an early international on-line services network built using microcomputers. Based on software developed in Germany by GeoNet Systems GmbH in the early 1980s, and completed in the early 1990s, it was one of the first networks to offer a ...

. The

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

also measured the quake at 6.5, at a depth of . The quake caused moderate damage in the wider Marlborough area and

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by me ...

, the nation's capital city north of the epicentre. Only minor injuries were reported. Several aftershocks occurred during 21–29 July. The Seddon earthquake is considered the first of an

earthquake doublet __NOTOC__ In seismology, doublet earthquakes – and more generally, multiplet earthquakes – were originally identified as multiple earthquakes with nearly identical waveforms originating from the same Epicenter, location. They are now characteri ...

, with a second earthquake of similar magnitude occurring on 16 August 2013.

Earthquake

Foreshocks

The earthquake was preceded by a series of foreshocks, the largest of which had a magnitude of 5.7. Below is a list of all foreshocks magnitudes 5.0 and above that occurred in the region between 19 July 2013 and 21 July 2013.

Aftershocks

The earthquake generated a series of aftershocks, the largest of which had a magnitude of 5.4. Below is a list of all aftershocks magnitudes 5.0 and above that occurred in the region between 21 July 2013 and 2 August 2013.

Damage

The quake resulted in varying degrees of damage to thirty-five buildings within the Wellington CBD with glass from broken windows falling onto the main thoroughfares of

Lambton Quay Lambton Quay (once known as The Beach) is the heart of the central business district of Wellington, the capital city of New Zealand. Originally, as the name implies, it was the high-water line of the foreshore, and sometimes the sea would roll ...

, Featherston Street, and

Willis Street Willis Street is a prominent street in the central business district of Wellington, the capital city of New Zealand. Along with Courtenay Place, Manners Street and Lambton Quay, the lower reaches of Willis Street form part of the "Golden Mile" ...

. Damage was also caused in

Paraparaumu Paraparaumu () is a town in the south-western North Island of New Zealand. It lies on the Kapiti Coast, north of the nation's capital city, Wellington. Like other towns in the area, it has a partner settlement at the coast called Paraparaumu Bea ...

Wainuiomata Wainuiomata () is a large suburb of Lower Hutt, in the Wellington Region of New Zealand's North Island. Origin of name The word 'Wainui-o-mata' is a Māori name made up of the words Wai = water, Nui = big, O = of, and Mata – which could refer ...

Porirua Porirua, ( mi, Pari-ā-Rua) a city in the Wellington Region of the North Island of New Zealand, is one of the four cities that constitute the Wellington metropolitan area. The name 'Porirua' is a corruption of 'Pari-rua', meaning "the tide swee ...

and the

Hutt Valley The Hutt Valley (or 'The Hutt') is the large area of fairly flat land in the Hutt River valley in the Wellington region of New Zealand. Like the river that flows through it, it takes its name from Sir William Hutt, a director of the New Zeala ...

in the North Island. The Wellington Region emergency management office was activated on the evening of 21 July, as were those in the lower part of the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

. On 22 July parts of Wellington's

central business district A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city ...

were closed to the public to allow for inspections to buildings with damaged and potentially dangerous façades. Four people were injured in the quake, which lasted for 20 seconds, blowing out windows, cracking concrete and swaying buildings.

References

External links

Cook Strait earthquakes, science update
–

GNS Science GNS Science ( mi, Te Pū Ao), 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 sc ...