Elemental Imagery

So looking back in the text, I noticed several elemental words referencing to wind, earth, fire, and water. The characters use these words to describe themselves and the interactions with other people. I was just wondering about the significance of using words along this theme. Is it just for vivid imagery or does it have another meaning? We compared the characters in the book to the birds on the italicized section on pages 52 and 53 who fly through the air(wind) and Louis compares himself to a tree in the earth. And the title of the book itself is The Waves. This all might just be in my head, but I thought it was an interesting point.

An example is on page 28 when Jinny is describing herself, “my thin legs ripple like a stalk in the wind” and “I leap like one of those flames that run between the cracks of the earth”.