WELLINGTON, Jan. 20 (Xinhuanet) -- A swarm of earthquakes that shook the lower North Island of New Zealand on Tuesday does not indicate a massive tremor is around the corner, the Institute of Geological and Nuclear Sciences (GNS) has said.
Ten earthquakes were recorded over a 10-hour period, with the biggest reaching 5.3 on the Richter scale and seven centered 40km southeast of Martinborough in the Wairarapa near Wellington.
GNS seismologist Martin Reyners told New Zealand Press Association Thursday that the sequence of the earthquakes was verysimilar to a pattern experienced in 1990 near Cape Palliser in thesouthern Wairarapa.
"We know that didn't lead to something larger," he said.
GNS scientists had completed preliminary studies into the cluster of earthquakes which began at 1.38pm on Tuesday with a 4.4tremor centered 30km northwest of Porirua, 20km north of Wellington, at a depth of 50km.
"The deeper earthquake Tuesday afternoon west of Porirua, we know occurred in the top of the Pacific plate," Reyners said.
"But the earthquakes off the Wairarapa we're still struggling with because they're offshore and our station coverage isn't so good because the nearest station is a bit further away."
The 10 earthquakes at this stage appeared to be a coincidence, he said.
The GNS would conduct further studies into the earthquakes to determine what they meant for the plates under the Wellington region, he said.
Some major earthquakes had a cluster of tremors beforehand but others, such as the 1931 New Zealand's Napier quake, had none, according to the seismologist.
But Tuesday's swarm and Boxing Day's 9.0 earthquake off the coast of Sumatra, Indonesia, were a timely reminder that larger earthquakes happened and people should have a survival kit ready, Reyners said.
However, he said there was no need for concern. Enditem