The Port Hills Fault is an active seismic fault

Active fault

An active fault is a fault that is likely to have another earthquake sometime in the future. Faults are commonly considered to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years....

 running under the Port Hills

Port Hills

The Port Hills form the northern rim of the ancient Lyttelton volcano, separating the port of Lyttelton from the city of Christchurch in Canterbury, New Zealand...

 near Christchurch

Christchurch

Christchurch is the largest city in the South Island of New Zealand, and the country's second-largest urban area after Auckland. It lies one third of the way down the South Island's east coast, just north of Banks Peninsula which itself, since 2006, lies within the formal limits of...

 in the middle of New Zealand's South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

.

Christchurch earthquake

A 6.3-magnitude

Richter magnitude scale

The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....

 earthquake occurred on the Port Hills Fault at on local time (23:51 UTC

Coordinated Universal Time

Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

), causing widespread damage and multiple fatalities. The earthquake was centred 2 kilometres (1.2 mi) west of the town of Lyttelton

Lyttelton, New Zealand

Lyttelton is a port town on the north shore of Lyttelton Harbour close to Banks Peninsula, a suburb of Christchurch on the eastern coast of the South Island of New Zealand....

, and 10 kilometres (6 mi) south-east of the centre of Christchurch

Christchurch

Christchurch is the largest city in the South Island of New Zealand, and the country's second-largest urban area after Auckland. It lies one third of the way down the South Island's east coast, just north of Banks Peninsula which itself, since 2006, lies within the formal limits of...

, New Zealand's second-most populous city. It followed nearly six months after the 7.1 magnitude 2010 Canterbury earthquake

2010 Canterbury earthquake

The 2010 Canterbury earthquake was a 7.1 magnitude earthquake, which struck the South Island of New Zealand at 4:35 am on local time ....

that caused significant damage to the region but no direct fatalities.