July 25, 2017

Latest Christchurch tremors on different faultline to February quake

It is time for the earthquake family to go and have a holiday somewhere else on the planet - preferably where no one lives.

Yesterday’s major earthquakes in Christchurch,New Zealand were on a different faultline to the one which devastated the city on 22nd February seismologists say.

GNS Science seismologist Bill Fry said yesterday’s 5.6 and 6.3 earthquakes were on a fault structure 2-3km south of the Port Hills fault which ruptured for the February 22 earthquake.

He said it was likely that stresses from the first shake triggered the second one.

“Technically this makes the magnitude 5.6 a foreshock, or precursor, of the magnitude 6.3,” he said.

“But overall they are still part of same aftershock sequence to the September earthquake.”

However, Dr Fry said the energy released in both earthquakes was high, as it had been for most of the earthquakes since the first one on September 4 which measured 7.1.

He said the dominant energy was horizontal, which meant it would have felt slightly different to the February earthquake, for which the dominant energy was vertical.