Underwater noise generated by the detonation of historical ordnance in the Baltic Sea, Lithuania: potential ecological impacts on marine life

The removal of ordnance and ammunition followed by high levels of impulsive noise is implemented yearly in the Lithuanian area of the Baltic Sea. During the international naval exercise Open Spirit (Summer 2013), an acoustical survey (using submersible cable hydrophone) was conducted in order to measure the underwater impulsive noise levels produced by controlled detonation and to assess their potential ecological impacts. The findings indicate a high noise energy level of explosions having a particularly small weight of charges, reaching up to 190 dB (in low-frequency bands) and theoretical estimations of the initial shock wave of 276 dB.