Earth's Structure and Plate Boundaries

Earth's Structure and Dynamics

• The lithosphere is the rigid outer layer of the Earth, comprising the crust and upper mantle.
• The asthenosphere is a layer in the upper mantle that exhibits ductile behaviour.
• The Mohorovičić discontinuity is the boundary between the Earth's crust and mantle.
• Pressure is the force per unit area exerted on a surface.
• Density is the mass per unit volume of a substance.
• Tectonic plates are large, rigid pieces of the Earth's lithosphere that move relative to each other.

Plate Boundaries

• Convergent boundaries occur where plates collide, leading to subduction or mountain building.

• Divergent boundaries occur where plates move apart, creating new crustal material.

• Transform boundaries occur where plates slide past each other horizontally.

• A fault is a fracture or zone of fractures in the Earth's crust where movement has occurred.

• Paleomagnetism is the study of the Earth's magnetic field in the past, using rocks as records.

• A hotspot is an area of volcanic activity that is not located on a plate boundary.

• A mid-ocean ridge is a long, undersea mountain chain that forms where plates diverge.

• A subduction zone is a region where one tectonic plate slides beneath another.

• Fault block mountains are created by the movement of faults, tilting and uplifting blocks of crust.

• A deep ocean trench is a deep valley in the ocean floor, often associated with subduction zones.

Convection Currents and Seismic Waves

•  Convection currents are movements within the Earth's mantle caused by differences in temperature and density. This drives plate motion.
• A seismic wave is an elastic wave generated by an earthquake or other seismic activity.
• A P-wave (primary wave) is a compressional wave.
• An S-wave (secondary wave) is a shear wave.
• A transverse wave causes the particles to vibrate perpendicular to the wave's direction of travel.
• A longitudinal wave causes the particles to vibrate parallel to the wave's direction of travel.

Earthquake Measurement and Location

• Moment magnitude is a measure of an earthquake's size, and is usually a more accurate measure than the Richter scale.
• The Richter scale is a logarithmic scale that measures the magnitude of earthquakes.
• The logarithmic scale is based on multiples of 10.
• Epicenter is the point on the Earth's surface directly above the focus of an earthquake.
• Focus is the point within the Earth where an earthquake rupture begins.
• A seismogram records seismic waves.
• A seismograph is an instrument that detects and records seismic waves.
• Triangulation is a method to determine the location of an earthquake's epicenter using data from multiple seismograph stations.

Explore the fascinating layers of the Earth and the dynamics of tectonic plates in this quiz. Test your knowledge on lithosphere, asthenosphere, and the different types of plate boundaries, including convergent, divergent, and transform. Understand how these geological processes shape our planet.