Magnitude 7 earthquake causes damage buildings and infrastructure

At 4am Friday morning a magnitude 7 earthquake struck New Zealand about 55 kilometres west Northwest of Christchurch, according to AIR.

Early images show toppled chimneys and parapets, and the collapse of many masonry infill walls. No casualties are feared at this point.

New Zealand's Ministry of Civil Defense and Emergency Management has activated the national emergency response centre.

Significant damage to infrastructure is feared, especially to sewer and water facilities in Christchurch.

Christchurch is the second largest city in New Zealand (population of 340,000 according to the 2006 Census) and the largest on the South Island.

The quake, initially estimated at a Richter magnitude of 7.4 by GeoNet, a hazard monitoring system in New Zealand, occurred at the boundary between the Pacific and Australia plates.

Aftershocks are continuing to occur, including a magnitude 5.7 aftershock that struck 20 minutes after the initial quake.

The Pacific Tsunami Warning Center has said there is no tsunami danger. 

Since records began, the largest magnitude earthquake to strike New Zealand was the 1931 magnitude 7.8 Hawke's Bay earthquake.

This event prompted a significant revision of the country's building codes. Over the years, New Zealand building code has advanced significantly, and its current building code is one of the most stringent in the world.