Another jolt in Christchurch last night and NZ through to the semi finals in Rugby World Cup!

Big quake rocks Christchurch
By Amelia Wade
5:30 AM Monday Oct 10, 2011
NZ Herald

Christchurch was rocked by a 5.5 magnitude aftershock last night - its biggest shake since June.

The tremor, at 8.34pm, was centred 10km northeast of Diamond Harbour and was 12km below the surface.

Last night, police said there were no reports of injury or damage although residents said the jolt was "big and noisy".

Aftershocks have been keeping Christchurch on edge since the 6.3 magnitude quake on February 22 that killed 181 people and caused billions of dollars worth of damage.

That quake was an aftershock of an even bigger 7.1 quake in September last year, which caused extensive damage but no deaths.

Christchurch Mayor Bob Parker was watching the All Blacks' Rugby World Cup quarterfinal match against Argentina with Prime Minister John Key at Hagley Park when last night's quake struck.

The tremor was definitely large enough to be cause for concern straight after it struck, Mr Parker said.

"It felt sharp enough to worry me but I haven't had any reports of anything too significant, so that's a relief."

The mayor said no one in the crowd seemed to worried about the "wobbly" quake and most stayed at the park after it struck.

"Everyone was very relaxed because we were out in the open. Nothing fell over or tipped up and the power stayed on.

"It was a very significant one and we were all bouncing around a little bit ... But there were quite a few people jumping up and shouting at the ref, and I don't think they even noticed."