*3.2. Characterization of Underwater Noise*

Two types of measurements were carried out for the monitoring of underwater sound in the Port of Cartagena:


The GPS position of each measuring point was also recorded for the subsequent spatial processing of the noise data. Figure 4 shows the position of the points.

**Figure 4.** (**left**) Location of all the measurements points. (**right**) Received voltage response (RVR) of the hydrophone used.

All the measurements were made by an IcListen HF smart hydrophone. This transducer has a sensitivity of approximately −170 dB re 1V/μPa with a bandwidth between 10 Hz and 98 kHz. The device acquires signal with a sampling frequency of 192 kS/s and its bit-depth is 24 bits. Figure 4 (right) shows its received voltage response (RVR) sensibility according to the frequency band.

In both types of measurements, the hydrophone was submerged 6 meters in a series of 3 min recordings of events due to:

