It said that thousands of residents reported experiencing moderate shaking after the shallow quake struck at 10:32 a.m. local time just 35 kilometers (22 miles) west of Milford Sound. The epicenter of the quake was registered at 5 kilometers (3.1 miles) deep.
Local media reported that residents in the lower part of New Zealand’s North Island also reported feeling the quake that lasted about 20-30 seconds. Te Ānau Helicopters employee Helen Archer told the NZHerald.co.nz that she was left feeling “sea-sick” from the quake.
“We certainly felt it. We’ve got cars out the front here and they were just rolling around in the carpark there.
“It wasn’t a violent earthquake. It was just jiggling,” she said. “We’re probably kind of used to earthquakes down here, but it was just rolling for a long time. It just kept going and we’re still feeling a bit yuck.”
The 6.0 magnitude quake was followed by another significant 5.9 magnitude quake at 10:34 a.m.
M6.0 quake causing moderate shaking near Milford Sound https://t.co/vvq6A2c234
— GeoNet (@geonet) June 24, 2020
A series of aftershocks have also been reported in the area.
M3.7 quake causing weak shaking near Milford Sound https://t.co/crNFLnHLMb
— GeoNet (@geonet) June 25, 2020
The region affected by the earthquake lies on what is known as the Alpine Fault.
This fault line, according to GNS Science, runs along New Zealand’s Southern Alps in the South Island and the east coast in the north. It is one of the world’s major tectonic features visible above sea-level and represents the meeting of the Pacific and Indo-Australian plates.
The fault has ruptured four times in the past 900 years, each time producing an earthquake of about magnitude 8.