how does the density of both the continental and oceanic crust cause this
The density of the continental and oceanic crust plays a significant role in the formation and movement of tectonic plates. The oceanic crust is denser than the continental crust, which causes it to sink beneath the continental crust in a process called subduction. This subduction creates deep ocean trenches and can also lead to the formation of volcanic arcs.
The density of the crust also affects the height of the Earth's surface. The continental crust is less dense than the oceanic crust, which causes it to rise higher above sea level. This is why continents are generally higher in elevation than the ocean floor.
Additionally, the density of the crust affects the way seismic waves travel through the Earth. Seismic waves travel faster through denser materials, so the density of the crust can affect the speed and direction of seismic waves during an earthquake.
Overall, the density of the continental and oceanic crust plays a crucial role in the formation and movement of tectonic plates, the height of the Earth's surface, and the behavior of seismic waves.