Variable Tremor
Variable Tremor

Variable tremor recorded on November 29, 2003 at the ABB short-period vertical seismic station. The event begins with a chaotic interval, followed by an impulsive low frequency event. Harmonic tremor follows, gliding first to high frequencies, then back to low. The event ends with faint harmonics. This audio record is sped up by a factor of 100 relative to the actual seismic signal.