<p>More aftershocks loom as likely new fault jolts </p><p>By PAUL GORMAN - The Press Last updated 05:00 09/09/2010</p><p>Earthquake-weary Christchurch residents now face a third possible aftershock source. </p><p>Scientists said yesterday morning's strong jolt was away from the fault trace that opened up across the Canterbury Plains on Saturday morning. </p><p>While its location was not yet known, the magnitude 5.1 quake at 7.49am yesterday appeared to have occurred on another fault, about six kilometres deep, between the Lyttelton road tunnel and the other side of the Port Hills, near Hillsborough. </p><p>Small aftershocks from yesterday's quake were being recorded last night. </p><p>About 350 aftershocks had been recorded since Saturday morning's magnitude 7.1 earthquake, with more than 150 strong enough to be felt and 10 shocks more than five in magnitude. </p><p>Canterbury University active tectonics and geomorphology lecturer Dr Mark Quigley said it was possible the Lyttelton earthquake was from a different fault. </p><p>However, he said that would not be known until more aftershock data was analysed. </p><p>The strongest aftershocks being experienced in Christchurch were coming from the Rolleston end of the previously hidden Canterbury fault. </p><p>"The major earthquake allowed most of the fault to slip, but there are sticky patches which are moving now because they are under more stress." </p><p>An aftershock of magnitude six was still possible, but Quigley was optimistic it might not occur. </p><p>"Significant aftershocks, such as the ones we have been feeling ... are likely to continue for weeks to months. </p><p>"I know this is distressing a lot of you, but I am hopeful that these aftershocks might be the biggest we get. However, they may not be, and we could get a bigger one months from now." </p><p>GNS Science natural hazards manager and earthquake geologist Dr Kelvin Berryman said the location of yesterday's Lyttelton quake was not on the same alignment as others, which meant it was unlikely to be on an extension of the Canterbury fault. "All earthquakes are on faults, but some faults are bigger than other faults." </p><p>A magnitude five quake centred 10km deep typically caused about 20 centimetres of slip. </p><p>"So this [Lyttelton] fault may only be 20cm long. It might just be an adjustment in a small piece of rock." </p><p>The zone producing the aftershocks on the new 22km-long, east-west Canterbury Plains fault trace was progressively extending further east and west due to the redistribution of stress in the ground and was now over 60km-long, he said. </p><p>However, the aftershocks would gradually become less frequent and smaller in magnitude. </p>