The Low Frequency Acoustic Seismic Experiment (LFASE) was conducted to
measure sound propagation and ambient noise above, at and below the sea
floor. To this end an array consisting of four geophone nodes was
introduced into a DSDP borehole. These seismic sensors were clamped inside
the borehole at various depths below the ocean floor. The geophone array
was connected by an electromechanical cable to a bottom reentry structure
(BCU frame) housing the Data Recording Unit (DRU), the Data Telemetry Unit
(DTU), the Bottom Control Unit (BCU) and the power supply.