The literary device the writer Dante uses in this excerpt for allowing the readers a better understanding of the scene is Imagery:
The ideas of a <em>"blasting sound"</em> or of a roar that causes <em>"both sides of the shore to tremble" </em>appeal to a person's sense of hearing. In sum, this can be identified as an imagery device since the words or phrases used allow the reader, appealing to human senses, to make a <u>visual or mental representation</u> of the story scenario.
It sounds like you are understanding what is being spoken about and you are showing that you are caring about what the person is saying while giving them your undivided attention.
