Surface wave

Definition

Surface waves are seismic waves that travel along the Earth's surface, causing most of the shaking felt during an earthquake. They typically arrive after the faster body waves and can result in significant ground displacement, contributing to the damage seen in structures during seismic events. These waves are crucial for understanding earthquake effects and evaluating seismic hazards.

5 Must Know Facts For Your Next Test

1. Surface waves generally have lower frequencies compared to body waves, which allows them to travel further and cause more destruction over larger areas.
2. They are typically categorized into two types: Rayleigh waves and Love waves, each with distinct motion patterns affecting how buildings sway during an earthquake.
3. Surface waves are responsible for most of the shaking felt on the Earth's surface, making them a primary focus in earthquake engineering and safety assessments.
4. Due to their slower speed, surface waves arrive after primary (P) and secondary (S) waves on a seismogram, providing insight into the location and magnitude of an earthquake.
5. In seismic reflection and refraction methods, surface waves can be utilized to image subsurface structures, providing valuable information in geological explorations.

Review Questions

• How do surface waves compare to body waves in terms of their impact on structures during an earthquake?
  • Surface waves differ from body waves primarily in their travel path and effects on structures. While body waves include P-waves and S-waves that propagate through the Earth’s interior, surface waves move along the Earth's exterior and typically cause more intense shaking. This intensity leads to greater damage to buildings and infrastructure as surface waves linger longer and create complex ground motions.
• Discuss the significance of Rayleigh and Love waves as types of surface waves in understanding earthquake hazards.
  • Rayleigh and Love waves play crucial roles in understanding earthquake hazards due to their distinct movement patterns. Rayleigh waves produce elliptical ground motion, causing both vertical and horizontal displacement, which can lead to severe structural damage. On the other hand, Love waves move horizontally, creating lateral forces that can be particularly destructive. Together, they highlight the potential risks associated with seismic events, informing engineering practices aimed at mitigating damage.
• Evaluate how surface waves can be utilized in seismic reflection and refraction methods for exploration purposes.
  • Surface waves can be effectively used in seismic reflection and refraction methods to gather information about subsurface geological structures. By analyzing how surface waves travel through different materials, geologists can infer properties such as density and composition. This technique allows for detailed imaging of underground formations, assisting in resource exploration and helping predict how these formations may respond during seismic events. The insights gained from studying surface wave behavior contribute to safer construction practices and better disaster preparedness.

Related terms

Rayleigh wave: A type of surface wave that causes both vertical and horizontal ground motion, moving in an elliptical motion similar to ocean waves.

Love wave: A type of surface wave that moves the ground side-to-side, causing horizontal displacement without vertical movement, often responsible for severe damage to buildings.

Seismogram:

A record produced by a seismograph that displays the motion of the ground as a function of time, capturing data from different seismic waves including surface waves.