This near-real-time audio stream originates from a seismometer at San Juan, Puerto Rico (IRIS/USGS station SJG). The low-frequency sounds of the solid Earth have been sped up by a factor of 1,000× to make them audible. As a result, frequencies have been transposed upward about 10 octaves. Each successive audio program (separated by a brief pause) compresses the last 96 hours into about 6 minutes (exactly 05:45) of listening time.