Christchurch Earthquake New Fault line

Geologists say today’s 7.1 magnitude quake 40km west of Christchurch city had an epicentre 10 km south-east of Darfield, but so far they have not been able to link it to a known fault line. “At this stage it appears the earthquake has not occurred on a known fault,” said GNS Science duty seismologist John Ristau. In the past few years, researchers have found that Canterbury is riddled with more earthquake-generating fault zones than previously thought – some as close as 20km to central Christchurch. Canterbury University scientists have said there are about 100 fault lines and fault segments around the region, rather than the half-dozen active faults that were known about 20 years ago. The closest known faults to Christchurch capable of generating powerful quakes are in the Rangiora-Cust area, near Hororata, and near Darfield. Regulators investigating Central Plains Water’s proposed Wairiri Dam in the area were told that the Hororata Fault “probably generates earthquakes of magnitude 7 or more every few thousand years”. CCID: 16375 [%Code Supp.%] That fault line passes about 6km south of the proposed dam site and under its head race. The Hororata fault between Darfield and Sheffield can be seen on the land surface because of the warping of alluvial plains, and other fault lines have been recognised between Darfield and Porters Pass. Canterbury University geological sciences department head Jarg Pettinga has said scientific advances in recent years have enabled the