The earth, our homeland, is a dynamic planet. Its surface has lofty mountains, high plateaus, large plains and deep valleys, and it is constantly undergoing changes inside and outside. The structure of the earth may be compared to that of an apple. The earth is called the blue planet – 71% of the earth is covered by water.
1. Structure of the Earth – Three Layers
On the basis of the study of earthquake waves, the spherical earth is found to be made of three concentric layers:
- The crust – the outermost layer
- The mantle – the layer beneath the crust
- The core – the innermost layer
| Layer | Share of the earth's volume | Boundary below it |
|---|---|---|
| Crust | Only 1% | Mohorovicic discontinuity (separates it from the mantle) |
| Mantle | 84% | Weichart-Gutenberg discontinuity (separates it from the core) |
| Core | 15% | – |