Aftershock Knocks out Power to Parts of Christchurch

Jul 11, 2011
Debbie Roome

Aerial Image of Earthquake-damaged Christchurch Cathedral - Debbie Roome

Christchurch was shaken by a 4.3 aftershock at 12:13pm on Monday 11th July. It was the strongest quake the city has experienced over the last week.

The 4.3 aftershock that jolted Christchurch on Monday 11th July was centered only 3 kilometers from Cathedral Square. It knocked out power to the suburbs of Belfast, Marshland, Brooklands and Spencerville, but this was restored just over an hour later.

Comments on the 4.3 Aftershock in Christchurch

Reports submitted to the Geonet website recorded that the 4.3 aftershock was felt across Christchurch and Canterbury.

A Burnside High School pupil was in a biology lesson and said she heard a rumbling and then everything started wobbling. “Everyone thought it was the class above stamping their feet, but then we realized it was an aftershock. We smiled at each other and went back to work.”

A mechanic in Hornby described the aftershock as a sharp jolt followed by gentle shaking. Another worker said the engine he was working on started rocking in front of him.

Status updates on Facebook revealed that the shaking was widespread and set hearts racing. Comments included the following: ‘our cockatiel is still yelling and hanging on the side of the cage ...’ ‘Good rumble in town. Bit noisy and rattling.’ ‘After not having felt one for quite awhile, that sure got the heart racing!’ ‘Makes me all shake and adrenaline rush. I don’t normally go to the door way but did for that one.’ ‘Hope everybody is ok! And has no more damage, hugs for all that need it!’ ‘Was the 4.3 today the Boxing Day fault or Port Hills fault, interested to find out? I’m picking the former.’

Geonet Earthquake Forecasts for Christchurch

The latest aftershock forecast map on Geonet runs from the June 13th 2011 to July 11th 2011. An average of 19 aftershocks between magnitude 4.0 and 4.9 were expected during this periods with an actual total of 27 occurring by the 11th July. Two aftershocks of magnitude 5.0 to 5.9 were forecast for the same period with three occurring.

The same forecast estimated that Christchurch had a three in ten chance of experiencing an earthquake of 6.0 or higher before the 14th July. After the 15th July, the estimated risk drops to three in ten.

In recent days, the number of aftershocks has decreased somewhat and their strength has also dropped. From midnight until 7pm on the 11th July, the city experienced 11 aftershocks with the 4.3 being the strongest. The smallest was of 2.4 magnitude.