Auckland was rocked by three earthquakes last night, the strongest measuring 4.5 on the Richter scale.
The tremors, which are unusual for Auckland, were described as shallow quakes and were felt as far afield as Te Atatu and Kawau Island.
The smaller earthquake at 8.24pm measured 3.7, the second (4.5) was at 9pm, and the third (3.8) was at 11.23.
The quakes were the largest in Auckland since 1970, when the city was shaken by a 4.7 quake centred in the Coromandel.
Meanwhile, quake-hardened Wellingtonians weren't fazed by a 4.4-magnitude earthquake off the coast of Picton, which was felt in the capital at 12.41pm yesterday.
GNS received "five or six" calls from concerned residents to report that quake, seismologist Bryan Field said.
The Auckland cluster of quakes, however, had resulted in about 1500 reports to the GNS website. "I think because Auckland don't have as many...it's a bit more scary," he said.
Volcano surveillance co-ordinator Brad Scott, of GNS Science, said quakes were felt on average every three to five years in Auckland.
The bigger earthquake was 15km deep and 30km east of Orewa.
Mr Scott said the shakes were not an indication of a larger one to follow. And they did not indicate that Auckland's volcanoes would erupt, because they were a long way from Auckland's volcanic field.
Two smaller quakes were registered in the same area on January 30, both measuring 2.7.
The bigger of the night's shakes was felt as far away as Kawau Island in the northern Hauraki Gulf and the third, which had a focal depth of 7km, was widely felt throughout Auckland.
The tremors also rippled through Warkworth to Waiheke Island and through central Auckland.
The second woke children in Sandringham where it rattled crockery and swung lights.
GNS Science records about 14,000 earthquakes in and around New Zealand each year. Most are small, but between 100 and 150 are big enough to be felt.
Mr Scott said: "Everybody should be aware of their responsibilities in terms of civil defence. It's a reminder of the geological environment we live in."
The Fire Service, Police and Ambulance services said there were no reports of any damage or injuries.
Stu Maaka, of Remuera, said: "I thought something had crashed. I've lived here 30 years and never felt anything like that."
A New Lynn resident out for the night said the jolt triggered an alarm at her place.
Mt Roskill resident Prem Nath's home shook for eight to 10 seconds.
"I called the police and they said there had been an earthquake. I felt things quiver. It was quite strange."
David Agnew, of Birkenhead, said residents in his street raced outside. "Everyone felt the shudder," he said.
Glenfield resident Tom Murray, who was at home with his wife Judy, said the whole house shook like mad.
"I thought maybe it was a bomb or something," the 65-year-old said.
"We were unsure what was happening. I got up and went charging around the house and up the drive and couldn't work out what had happened.
"I didn't even know we had earthquakes here. It was quite scary. It's the first earthquake I've felt."
The pair were sitting in the lounge of the five-bedroom house when they felt the second earthquake at 9pm. "The whole lounge suite was shaking and there was a big whoosh through the house and the house was vibrating."
He said there was no damage inside the house and he hoped there was no structural damage.
Another Glenfield resident, Amy Volk, said dozens of people in houses around her on Glenfield Rd went running into the street after the second quake.
"The whole house shook - my flatmate Dorothy [Hunt] thought the house was slipping away."
Rachael Pattinson, 35, of Browns Bay, said she had never experienced an earthquake and was terrified. "I thought the house was going to collapse."
Although Auckland is one of the least quake-prone areas it has had 35 earthquakes of more than 3 on the Richter scale since about 1830. Only one has caused significant damage.
- Additional reporting: NZPA