The cheek the nerve the gall the audacity and the gumption

Ineed asap i will give 30 pointsps: the last word says splits

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?

What is the thickest layer of earth called?