A monitoring facility includes at least one acoustic sensor arranged in a monitoring area to convert an acoustic wave picked up following the occurrence of an activity in the monitoring area into an information signal, and a processing device to receive the information signal. Also included is a system for transmitting at least one alarm and a database including, for each one of at least one predetermined reference activity, an occurrence of which is likely to generate acoustic waves in the monitoring area, reference characteristics relating to said predetermined reference activity. The processing device includes an analysis system to analyze the information signal according to reference characteristics of at least one predetermined reference activity of the database, and to activate the system for transmitting at least one alarm according to said analysis. Furthermore, at least one acoustic sensor is included to detect seismic waves propagating in a solid medium.