One. Earth's crust
One. Earth's crust
Earth's oceans dominate the surface, while continents and islands make up the remaining land areas.
Most of Earth is covered by oceans, seventy percent, and land only makes up a small portion, thirty percent.
Earth has more water than land. Seventy percent water, thirty percent land.
Continental crust is thicker, lighter, and forms landmasses,
while oceanic crust is thinner, denser, and forms ocean floors.
Continental crust is less dense, low density, and thicker,
allowing it to "float," above the mantle.
Subduction occurs because oceanic crust is heavier, so it moves under the lighter continental crust.
Two. Volcanoes
Two. Volcanoes
The type and location of volcano depend on magma composition and eruption style.
An active volcano shows signs of recent emissions and can erupt anytime, posing danger.
Shield volcanoes have low-viscosity lava, causing gentle eruptions.
Composite volcanoes are known for steep slopes and explosive eruptions.
Thick lava builds steep cores, while this lava spreads widely. Therefore, lava viscosity affects cone steepness.
Low-viscosity basaltic lava produces wide, gently sloping shield volcanoes.
Earthquakes and volcanoes are concentrated in areas of plate boundaries, like the Pacific Ring of Fire.
Crust movement contributes to mountain building.
Plate collisions uplift mountains and trigger earthquakes. Lithosphere is the rigid outer layer of Earth divided into plates. It consists of the crust and upper mantle. Plate movement controls the location of earthquakes, volcanoes, and mountains.