Fault Types and Wave Characteristics

The document continues to explore different wave types and fault classifications that are crucial for How Earthquakes Occur at Tectonic Plate Boundaries.

Definition: Love waves are transverse waves that move back and forth in their travel direction, similar to waves in a slinky laid on a table.

Definition: Faults are cracks in the Earth along which sides can move parallel to the crack.

The three main types of faults are:

Vocabulary:

• Thrust/Reverse Faults: Vertical slip where one block moves upward relative to another
• Normal Faults: Vertical slip where one block moves downward relative to another
• Strike-slip Faults: Horizontal slip where blocks move past each other sideways

Highlight: Understanding fault types is crucial for predicting and analyzing earthquake behavior and potential damage patterns.

Understanding Earthquakes and Seismic Measurement

An earthquake is defined as a sudden and violent shaking of the ground caused by crustal movements and mechanical wave propagation through rock layers. The science behind earthquake measurement involves several key components and locations.

Definition: A seismograph is a scientific instrument that records earthquake motions and seismic waves when they reach the instrument's location.

The main components of an earthquake include:

Vocabulary:

• Focus: The precise geographic location and depth where an earthquake initiates
• Seismic Waves: Mechanical energy propagating through Earth's layers
• Fault: A line where rock sections can move against each other

Highlight: Most earthquakes occur along faults, particularly at tectonic plate boundaries, which are massive breaks in Earth's lithosphere.

The four types of seismic waves include:

Example: Primary (P) waves are compressional waves that move fastest through all parts of Earth, similar to a compression spring.

Example: Secondary (S) waves are transverse waves that move like a rope being waved up and down, but cannot travel through Earth's liquid outer core.

Example: Rayleigh waves move in circular motions similar to ocean waves, with a distinctive retrograde motion.