hennemusic

The Foo Fighters and their fans shook the earth on Tuesday.

Literally.

Rolling Stone reports a Foo Fighters concert in New Zealand caused geological vibrations on par with “volcanic tremors,” according to scientists.

The vibrations emitted "a strong low signal," geologists at Auckland GeoNet reported. "The ground was shaking three times per second in a nice rhythmic motion." The recordings were taken at two monitoring stations located about a mile from the concert site at Western Springs.

Auckland GeoNet reports the first vibrations were recorded around 7:30pm, part way through the Tenacious D set, but the biggest shakes started at 8:20pm when the Foo Fighters took the stage, and then it all went quiet at 11pm when the gig ended.

The concert vibrations were recorded as a semi continuous harmonic signal with a peak osculation of 3Hz, ie the ground was shaking 3 times per second in a nice rhythmic motion. There were lulls in the signal between the songs and peaks in signal intensity during the songs.

The cause of the shaking was 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.

The sound system probably contributed as well, especially the bass frequencies coupling in to the earth. The signal is similar to volcanic tremor that is recorded at places like Mt Ruapehu and White Island.

Read the full report at Auckland GeoNet here.