Abstract: This investigation studies the effects of noise from near-shore marine drilling activity taken from hydrophone readings in the water column. Findings suggest that peak noise levels were emitted by hardrock rotary drilling in the low frequency range,
close to the source. Closer inspection of the geomorphology of the drill site revealed the
limestone rock substrata to be covered by an insulating layer of up to 20m of silty-sand.
Noise from drilling associated activity surpassed the literature supported 90 dB limit for all measured distances. Species most affected by increased decibel levels in the mid to low frequency range would be pelagic fish, though all marine animals in the area would have been affected. Noise levels were described across all frequency levels between 1 and 20,000Hz and in individual 1/3 octave ranges.
Amplitudes were calculated from peak-to-zero and root mean squared values. Sound propagation in tidal flows up to 1ms-1 was also studied. Activities, techniques and methods presented are comparable to those which would be used to study a marine energy device installation, in particular noise effects associated with drilling.
