How do we know Earth's internal structure? ...

[DyllonKazuo]

How do we know Earth's internal structure?

Question 2

Explain how oceanic crust is created and destroyed.

[mjbamaung]

Answer to Question 1

Seismic waves from earthquakes that pass through Earth's interior before being recorded by seismographs are used to reconstruct Earth's internal structure. Seismic waves are refracted or reflected at major density changes or phase changes. For example, S waves cannot pass through liquids, and this tells us that Earth's outer core is molten.

Answer to Question 2

Oceanic crust forms from volcanism at midoceanic ridges (powered by melt from the mantle) before moving away like a conveyor belt. Where that plate reaches a subduction zone, it dives down into the mantle, where it will eventually melt.

[DyllonKazuo]

TY

[mjbamaung]

You're welcome