Earth Science: Lithosphere and Plate Tectonics

Lithosphere

• The Earth's solid outer layer is known as the lithosphere.

Continental Drift

• Alfred Wegener, in 1912, proposed the theory of continental drift, explaining that continents move.
• He suggested that all landmasses were once joined together in a supercontinent called Pangaea.

Plate Tectonics

• The theory of Plate Tectonics explains that the Earth's surface is divided into large, rigid plates that move and interact.

Seismic Zones

• These zones mark the boundaries between five plates: North American, Caribbean, Cocos, Pacific, and Nazca.
• Friction caused by the interaction of these plates generates significant seismic activity.

Seismic Waves

• Compression Waves (P): Travel in a parallel direction, move through all materials (solids, liquids, and gasses) and are the fastest seismic waves.
• Shear Waves (S): Travel perpendicular to their direction of movement and only pass through solid materials, making them slower than P-waves.
• Surface Waves (R/L): Have a wave-like motion and exhibit the largest amplitude at the Earth's surface, with decreasing amplitude as depth increases.

Earthquake Measurement

• Hypocenter: The point within the Earth where an earthquake originates.
• Epicenter: The point on the Earth's surface directly above the hypocenter.
• Richter Scale: This scale measures the energy released by an earthquake.
• Mercalli Scale: This scale measures the intensity and the severity of an earthquake's effects on humans and structures.
• Magnitude: This refers to the strength of an earthquake.
• Intensity: This refers to the earthquake's effects.
• Seismograph: An instrument used to detect and record seismic waves.

Weathering

• Weathering is the process by which rocks are broken down by natural forces like water, air, and ice.

Geology

• The study of the Earth's composition, structure, and history is called geology.

Explore the foundations of Earth's geology with this quiz on the lithosphere, continental drift, and plate tectonics. Test your knowledge about seismic waves and the Earth's seismic zones. Gain a deeper understanding of how tectonic activity shapes our planet.