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A swarm of earthquakes accompanied by alarming bangs is rocking Matata, raising fears a big one may be about to strike.
Another quake hit the area at 5.58am this morning, centred 10km underground and 10km north of Reporoa. GNS Science said it was felt in Waikite Valley and Rotorua.
Early yesterday another quake, measuring 3.6 on the Richter scale, shook homes. More than 150 tremors have been recorded in the Bay of Plenty town this month.
GNS Science says the swarm is not necessarily a sign a giant quake is coming, but is warning residents not to be lax.
"At this stage, we're just considering that it's part of the ongoing activity in the area," duty seismologist Martin Reyners said.
He said the magnitude 6.1 Edgecumbe earthquake, which struck 20 years ago this month, was a reminder to Bay of Plenty people that they lived in a major seismic zone.
"They should always be prepared [for a large quake]," he said.
The Edgecumbe quake warped rail lines, levelled houses and destroyed a dairy factory. It also opened up a faultline several kilometres long.
Violent shaking was felt in nearby Matata and swarms of quakes shook the area before it struck.
The current swarm in Matata is the latest threat to the tiny coastal town, much of which was destroyed by floods and landslides in May 2005.
Apart from the natural phenomena, an arsonist is still at large after razing several buildings.
Rob Pearce, who lost his house in the floods, said the earthquakes were putting people on edge.
"You get a shake and everybody talks about it," he said. "In the back of their minds, they are thinking maybe the big one might come."
He said many of the quakes, including yesterday's, were accompanied by a loud bang. "You hear the bang first and then you feel the rumble and things start shaking."
Narelle Boonen said the sound was "like thunder rolling in the hills" and her children were getting used to running and standing in doorways.
"There's an expectation that there is going to be a big one," she said.
Mr Pearce and Ms Boonen have emergency kits and Matata School has been practising earthquake drills.
Mr Reyners said Matata had experienced earthquake swarms on and off since 2005 and the current quakes were small, measuring between 3 and 4 on the Richter scale.
"The people in Matata are feeling them because they're reasonably shallow," he said.
The average depth - about 5km - was normal for the whole Taupo volcanic zone, stretching from White Island to Mt Ruapehu.
Mr Reyners said it also was important to keep the number of quakes in perspective.
Wellington, for example, had an average six earthquakes a day, or 180 a month, while swarms afflicted Taupo for 10 months in 1964 without leading to a major event.
The bang or crack before the quakes was the "P wave", when sound in rock reaches the surface and becomes sound in the air.
"Generally, the Matata people will hear the crack and they will feel it [the earthquake] pretty soon afterwards because it's close."
Shaking is known as the S wave.
