Underwater sound is not the same.

Some alarming statements about loud sounds underwater may be based on a simple misunderstanding. Serious confusion can result from incorrectly stating sound levels as though the sounds were being produced in air when they are actually being produced in water.

Imagine being told that it's 30 degrees outside. What would you conclude?
If it were 30 degrees Celsius, you might choose to wear sandals and shorts
If it were 30 degrees Fahrenheit, you had better bundle up because it's freezing!
This confusion can arise because Fahrenheit and Celsius are very different scales of temperature measurement which both employ the same word: "degrees."

The measurement scales for sound in water and sound in air are also different scales of measurement, both using the word "decibels." However, there is a difference of 63 dB between the two sound scales. 26 dB of this difference is due to conventional choices of the sound reference level. In air, the reference level is 20 microPascals; in water, the reference level is 1 microPascal. The remaining difference relates to differences in the density and compressibility of air and water.

For instance, when discussing the loudness of sounds: "160 decibels" in air can cause tissue damage to the ears of mammals. However, underwater "160 decibels" is equivalent to 100 dB in-air. This is the sound level that one would hear when standing three feet from a loud radio.

Similarly a level of 125 dB in-water is equivalent to approximately 65 dB in-air. This is the level one would hear when having a normal conversation.