The sound you hear is a conversion of seismic records of Turrialba Volcano to be heard by the human ear.
Using computer programs we transform seismic records in this case the seismogram located in the central crater of the Turrialba Volcano (VTun) at a frequency audible to the human ear.
This is done to recognize patterns in seismic activity of the volcano.
The audio clip was posted by Floribeth Vega-Solano of the OVSICORI-UNA n Soundcloud.