Another large shake on both sides of Cook Strait is highly likely over the next week, experts say.
The chance of a jolt of at least magnitude 5 in the next seven days is 82 per cent, according to GNS Science seismologists, and the likelihood of a magnitude 6 or more quake is about 16 per cent.
Seismologist Caroline Holden warned people to be vigilant and expect another large shake.Since Friday afternoon's 6.6 tremor, there had been another 62 aftershocks reaching magnitude 4 or more, by yesterday evening.
Dr Holden's colleague Martin Reyners said the area near Seddon where the earthquakes were recurring was known as an active one. There was a magnitude 6 quake there in 1966, and another in 1977.
The level of horizontal acceleration, which is the amount of movement people feel from a quake, was similar to that felt during the Christchurch earthquakes, but not as significant.
"It's a different experience for everyone, depending on what soil your house is built on. At its worst acceleration, there were reports of people not being able to stay standing upright," he said.
The sequence of quakes was slowly tracking southwest, away from Wellington, but on to land in Marlborough.
"Friday's quake was situated so that the people of Seddon were sitting pretty much on top of it, which explains the damage. Each quake changes the stresses in the fault. In areas where the stress has gone up, near a fault, it can trigger another event."
In the case of the recent quakes, there had been some triggering as the stresses shifted south. This would mean the effects would be felt less in Wellington, but more in Seddon.
CAPITAL OPEN FOR BUSINESS
Wellingtonians can re-enter the central city today with "a degree of confidence," the region's Civil Defence controller has said.
Bruce Pepperell said road and building infrastructure had been checked thoroughly after Friday's 6.6 magnitude earthquake and Wellington city had been declared open for business.
"We're 99 per cent back to normal, albeit a new normal," he said this morning.
Lukes Lane, which links Manners and Taranaki Sts, remained cordoned off and its surrounding buildings empty this morning while an unstable lift shaft was demolished.
Motorists were being asked to avoid the area if possible.
Pepperell said he was aware of "one or two" buildings that were closed this morning.
Employers were doing a good job of communicating building safety issues to their staff, he said.
"They have a lot more of an understanding about their responsibility ... after last month's earthquake," he said.
A Greater Wellington Regional Council spokeswoman said all bus, train and harbour ferry services in the region were running to normal timetables this morning.
Ministry of Education Deputy Secretary Andrew Hampton said last night that the majority of schools, early childhood education providers and tertiary institutions in quake-affected areas were expected to open today.
"To date we have only received reports of superficial damage to buildings and property," he said.
"However, decisions on whether to open are made by the providers themselves, so if parents or students are in any doubt they should check with directly with the school, early childhood education service or tertiary institution."
More information is available on the Ministry's website: www.minedu.govt.nz
- © Fairfax NZ News
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