Shakes 'nothing to worry about'

The southern Hawke's Bay coastal settlement of Porangahau is one of the country's earthquake hotspots, but scientists say recent quakes are nothing to worry about.
Between May 30 and July 15, Porangahau experienced 30 earthquakes greater than magnitude 3.0, with depths less than 35km.
Earlier this month, on July 4, there were 10 of these small quakes, including two over magnitude 4.0 and one over magnitude 5.0 and, on July 15, three of the day's shakes were shallower than 20m.
GNS duty seismologist Caroline Holden said that the cluster of quakes was nothing to worry about and is a normal part of east coast living.
"In the last two months there have been about six events above magnitude 4, but clusters are not unusual - there was another swarm of clusters last September," she said. "The whole of the North Island is on a subduction interface, you basically have two plates, the Australian Plate sitting above the Pacific Plate."
She said it was the movement of these plates, that met each other under Porangahau, that caused the clusters.
"The Pacific plate is coming right under the North Island so when the two plates move, they aren't doing it smoothly.
"Sometimes they move against each other quite fast which causes large earthquakes, and sometimes they move apart slowly and it takes weeks or months to do that same movement and it won't cause any shaking," she said.
Despite the frequency and magnitude of the cluster, Porangahau residents said they were not affecting their lives compared with those that were affecting people in Christchurch.
"There was one a few weeks back that felt like it was the start of something, but it never came," said local mechanic Bob Fair.
"We are used to them by now. It's nothing compared to what they must be going through in Christchurch,"
Another resident, Paul Sciascia, said his young son, Matawhero, was sometimes afraid of the earthquakes.
"I haven't been here for the majority of them, maybe only two of them I have been here, but it's taking its toll on the young fella slowly but surely."
Mr Sciascia said his son takes refuge at his grandparents' house next to the local marae when he gets frightened.
"It sounds like a train coming, and I don't like it," Matawhero explained.
"There was one at night and I could hear it."
Other Porangahau residents said this particular cluster of small earthquakes was nothing compared with previous years, when chimneys were knocked off and furniture fell over.
Ms Holden said earthquake clusters in the Hawke's Bay region were common about once a year.