In 1994 Rage Against the Machine was performing at Pinkpop (Netherlands) and the audience caused an earthquake of a magnitude 1 on the Richter scale. That is a

In 1994 Rage Against the Machine was performing at Pinkpop (Netherlands) and the audience caused an earthquake of a magnitude 1 on the Richter scale. That is a lot of energy, but still at the bottom of the Richter scale. According to Wikipedia: "Microearthquakes, not felt, or felt rarely. Recorded by seismographs.", occurring several million times per year. Seismographs are just very sensitive.