M6.0 - SOUTH ISLAND OF NEW ZEALAND

Tectonic Summary

The M6.0 June 13, 2011 South Island, New Zealand earthquake is a continuing part of the earthquake sequence that initiated with the M 7.0 September 3, 2010 Darfield, New Zealand event. The June 13, M 6.0 earthquake is a dominantly strike-slip faulting event near the eastern end of the inferred rupture of the 21 February 2011 M 6.1 earthquake. Both this M 6.0 quake and the previous M 6.1 event have an inferred fault plane striking approximately east-northeast. The entire earthquake sequence is broadly associated with regional plate boundary deformation as the Pacific and Australia plates interact in the central South Island, New Zealand.

This latest earthquake, similar to the February 21 event, is close to the main population centers of Christchurch, New Zealand. This region has suffered significant casualties and damage to buildings, infrastructure, and lifelines from a series of events particularly since the February 21 earthquake. Additionally, the earthquakes close to Christchurch caused substantial liquefaction in residential areas. The June 13 earthquake was preceded by a nearby M 5.2 foreshock, about 1 hour and 20 minutes earlier. There is no specific surface fault that has been observed for the post-September 3 earthquakes near Christchurch, nor evidence directly linking them to the observed September surface fault rupture. There have however been a substantial number of aftershocks forming a continuous swath of seismicity extending from the September 3 events to the June 13 earthquake.

Earthquake Information for New Zealand