Calibration of Ewing acoustic sources

 
Photos Courtesy of Nathalie Jaquet and Jonathan Gordon


As anthropogenic noise in the oceans increases we are becoming increasingly aware of the possibility of its impact on marine mammals.  As part of Lamont-Doherty Earth Observatory and the National Science Foundation's commitment to determining any possible impact on marine mammals from active source seismics, we participated in SWSS (Sperm Whale Seismic Study) in the summer of 2003.  In addition, we made the first well-calibrated broad-frequency measurements of the RV Ewing's acoustic sources to accurately determine source levels at a range of frequency-of-concern to marine mammals (1Hz - 25kHz).  Until source levels are accurately constrained at a range of frequencies it will be very difficult to predict, and therefore prevent, the circumstances under which marine mammal disturbance might occur.