Foo Fighters concert causes earthquake

Apparently, Dave Grohl & co. really rocked the place: Foo Fighters Concert Registers Earthquake-Level Geological Tremors:

During a Dec. 13 show in Auckland, New Zealand, the Foos and some 50,000 fans caused tremors similar to a volcanic event.

According to two seismic stations outside the Western Springs stadium -- 1.5 and 2 kilometers from the locale respectively – a strong low frequency of tremors were detected at the time of the show, correlating specifically with the highs and lows of the performance. The levels recorded were consistent with that of volcanic activity.

"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," Geonet states.

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