Earth's Interior and Plate Tectonics

Study Notes

Composed of several layers:
- Crust: outermost solid layer, ranging in thickness from 5-70 km
- Mantle: thick layer beneath the crust, divided into upper and lower mantle
- Outer Core: liquid iron-nickel alloy, responsible for generating Earth's magnetic field
- Inner Core: solid, iron-nickel alloy at the center of the Earth

Theory that explains the movement of Earth's lithosphere (outermost solid layer)
Comprises 7 major plates and several smaller ones
Plates move relative to each other, resulting in:
- Divergent motion: plates move apart, creating new crust
- Convergent motion: plates collide, resulting in subduction or collision
- Transform motion: plates slide past each other horizontally

Theory that continents have moved over time and were once joined together
Evidence:
- Fit of the continents: puzzle-like fit of the continents
- Similarity of coastlines: identical rock formations and fossils on different continents
- Paleomagnetism: magnetism in rocks indicates continents have moved over time

Result from the movement of tectonic plates
Occur when there is a sudden release of energy in the Earth's crust
Types:
- Tectonic earthquakes: caused by plate movement
- Volcanic earthquakes: caused by volcanic activity
- Collapse earthquakes: caused by underground caverns or voids

Landforms that occur when magma from the Earth's interior rises to the surface
Types:
- Shield volcanoes: gently sloping, formed by lava flows
- Composite volcanoes: steep-sided, formed by a combination of lava and ash
- Cinder cones: small, formed by ash accumulation
Volcanic activity:
- Eruption: release of magma and gases from the Earth's surface
- Lava flow: molten rock that flows from a volcano
- Pyroclastic flow: fast-moving, hot cloud of ash and gas