Plate Tectonics Basics

Plate Tectonics

• Theory: The Earth's lithosphere is broken into large plates that move relative to each other.
• Types of plate boundaries:
  1. Divergent: Plates move apart, new crust forms (e.g., mid-ocean ridges).
  2. Convergent: Plates move towards each other, resulting in subduction or collision.
  3. Transform: Plates slide past each other horizontally (e.g., San Andreas Fault).
• Plate movement:
  • Convection currents: Heat from the Earth's core drives plate movement.
  • Slab pull: Dense plates sink into the mantle, pulling the rest of the plate with them.

Seismic Waves

• Types of seismic waves:
  1. P-waves (primary waves):
     • Compressional waves that travel through the Earth's interior.
     • Can travel through solid, liquid, and gaseous materials.
  2. S-waves (shear waves):
     • Waves that travel through the Earth's interior, causing perpendicular motion.
     • Can only travel through solid materials.
  3. Surface waves:
     • Waves that travel along the Earth's surface, causing horizontal motion.
• Seismic wave characteristics:
  • Velocity: P-waves travel faster than S-waves.
  • Amplitude: Wave amplitude decreases with distance from the epicenter.

Volcanic Eruptions

• Types of volcanic eruptions:
  1. Explosive eruptions: Violent release of gas and rock, often with a loud noise.
  2. Effusive eruptions: Steady flow of lava, often with minimal explosive activity.
• Factors influencing eruptions:
  • Magma composition: Gas content, temperature, and viscosity affect eruption style.
  • Pressure buildup: Pressure from magma and gas accumulation can lead to explosive eruptions.
• Volcanic features:
  • Volcanic arcs: Chains of volcanoes formed by subduction of oceanic plates.
  • Calderas: Large depressions formed by collapse following a massive eruption.

Plate Tectonics

• The Earth's lithosphere is broken into large plates that move relative to each other.
• There are three types of plate boundaries:
  • Divergent: Plates move apart, and new crust forms, such as at mid-ocean ridges.
  • Convergent: Plates move towards each other, resulting in subduction or collision.
  • Transform: Plates slide past each other horizontally, such as at the San Andreas Fault.
• Plate movement is driven by:
  • Convection currents: Heat from the Earth's core drives plate movement.
  • Slab pull: Dense plates sink into the mantle, pulling the rest of the plate with them.

Seismic Waves

• There are three types of seismic waves:
  • P-waves (primary waves): Compressional waves that travel through the Earth's interior, can travel through solid, liquid, and gaseous materials.
  • S-waves (shear waves): Waves that travel through the Earth's interior, causing perpendicular motion, can only travel through solid materials.
  • Surface waves: Waves that travel along the Earth's surface, causing horizontal motion.
• Seismic wave characteristics:
  • Velocity: P-waves travel faster than S-waves.
  • Amplitude: Wave amplitude decreases with distance from the epicenter.

Volcanic Eruptions

• There are two types of volcanic eruptions:
  • Explosive eruptions: Violent release of gas and rock, often with a loud noise.
  • Effusive eruptions: Steady flow of lava, often with minimal explosive activity.
• Factors influencing eruptions:
  • Magma composition: Gas content, temperature, and viscosity affect eruption style.
  • Pressure buildup: Pressure from magma and gas accumulation can lead to explosive eruptions.
• Volcanic features:
  • Volcanic arcs: Chains of volcanoes formed by subduction of oceanic plates.
  • Calderas: Large depressions formed by collapse following a massive eruption.

Understand the fundamental concepts of plate tectonics, including the theory, types of plate boundaries, and plate movement. Learn about divergent, convergent, and transform plate boundaries, as well as convection currents driving plate movement.