The stamping feet of 50,000 Foo Fighters fans literally shook the earth under Auckland, seismic tests show.
Geonet today said seismic stations set up in Herne Bay and Eden Park recorded ground movement similar to a volcanic tremor as the band played through their nearly three-hour set at Western Springs on Tuesday.
The first vibrations were recorded around 7:30pm, part way through the set of support band Tenacious D.
But the biggest shakes came after the Foo Fighters took to the stage at about 8:20pm.
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Concert vibrations were recorded at 3Hz, with the ground shaking three times per second in a regular rhythm.
There were lulls in the signal between songs and peaks in intensity during the songs, Geonet said.
At its peak, the seismic signal was similar to that of a volcanic tremor that recorded at places like Mt Ruapehu and White Island, it said.
"The cause of the shaking is most likely the weight of the 50,000 fans dancing, as 50,000 fans is equal to around 5,000 tonnes of mass moving (or moshing) on the ground for the duration of the concert. This set up a nice harmonic vibration in the ground."
Seismic activity went quiet at 11pm after the Foo Fighters' final encore.
The shaking was similar to that caused by 60,000 fans cheering the All Blacks' Rugby World Cup victory at Eden Park.
A seismometer buried 25 metres beneath the stadium spiking activity after the final whistle blew at 10:30pm on October 23.