2013 Seddon earthquake


The 2013 Seddon earthquake measured 6.5 on the scale and was centred in New Zealand's Cook Strait, around east of the town of Seddon in Marlborough. The earthquake struck at 5:09:30 pm on Sunday 21 July 2013 at a depth of, according to Geonet. The United States Geological Survey also measured the quake at 6.5, at a depth of. The quake caused moderate damage in the wider Marlborough area and Wellington, 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, 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.
Date Time Magnitude Magnitude Magnitude EpicentreDepth
19 July 20139:06:39 am5.55.75.730 km east of Seddon17 km
21 July 20137:17:10 am5.95.85.830 km east of Seddon20 km

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.
Date Time Magnitude Magnitude Magnitude EpicentreDepth
21 July 20135:09:30 pm6.56.16.525 km east of Seddon13 km
21 July 20135:13:50 pm5.35.230 km east of Seddon13 km
29 July 20131:07:14 am4.95.420 km east of Seddon12 km
2 August 201312:56:13 am4.75.220 km east of Seddon6 km

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, Featherston Street, and Willis Street. Damage was also caused in Paraparaumu, Wainuiomata, Porirua and the Hutt Valley 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. On 22 July parts of Wellington's central business district 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.