Cook Strait Earthquakes

Earthquake activity in the Cook Strait Canyon, which began on Friday morning, is continuing.

Sunday, 21st July 2013

Earthquake activity centred in Cook Strait 30 km east of Seddon began on Friday morning, when a magnitude 5.7 earthquake struck at 9:07 a.m. The shallow quake, 16 km deep, was centred on the southern bank of the Cook Strait Canyon and was felt from Auckland to Christchurch.

Aftershocks followed, the most significant was a magnitude 4.5 event at 3:21 on Friday afternoon.

Activity eased until this morning, when a magnitude 5.8 earthquake, slightly deeper at 19 km, woke residents of Wellington and Marlborough at 7:17. A magnitude 4.2 foreshock woke some people at 7:04 a.m.

[click for larger image] This snapshot of GeoNet’s national seismograph network clearly shows the trace of this morning’s foreshock, quickly followed by the strong trace of the main event.

Activity has continued, with twenty magnitude 3 aftershocks and five magnitude 4 aftershocks being recorded by 11 o’clock this morning.

[click for larger image] This snapshot of GeoNet’s national seismograph network shows the traces of the earthquakes recorded this morning. The strong trace on the left is the magnitude 5.8 earthquake and the trace on the right is the magnitude 4.9 quake felt at 10:55.

Swarms of earthquakes occurred near Seddon in 2003, 2005, 2007 and 2008. A magnitude 6.1 quake struck the area in April 1966, causing damage in both Wellington and Marlborough.

Information on Friday’s earthquakes has already disappeared from the quakes pages on the GeoNet website, but readers can retrieve the information by following the links above. Even this morning’s magnitude 5.8 quake has been buried by the aftershocks exceeding the website’s limited listing of the most recent 30 events.

[Compiled from data supplied by GeoNet. ]

One Response to “Cook Strait Earthquakes”

  1. Lizzie from Gizzie says:

    Wellingtonians will be beginning to feel a little ‘wobbly’ by now!!!!!

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