General Contractor Practice Exam

In terms of seismic activity, which type of earthquake results in vertical and lateral motion?

1. Surface waves

2. Body waves

3. Secondary waves

4. P-waves

The correct answer is: Surface waves

The type of earthquake that results in vertical and lateral motion is surface waves. These waves travel along the Earth's surface and are responsible for the most significant shaking felt during an earthquake. They tend to have lower frequencies and longer wavelengths, causing both vertical and horizontal displacements of the ground. This combination of movement often results in the most destructive effects during an earthquake, as buildings and structures can experience intense lateral shaking in addition to up-and-down motion. Body waves, on the other hand, are categorized into primary (P-waves) and secondary (S-waves). P-waves are compressional waves that move through the Earth and cause particles to move in the same direction as the wave, resulting in a push-pull motion. S-waves, which are shear waves, cause particles to move perpendicular to the wave direction, but they do not travel through liquids and primarily cause vertical motion. However, they do not produce the same extensive lateral and vertical movement experienced with surface waves. Therefore, surface waves are recognized for their destructive capacity due to the combined vertical and lateral displacement they induce upon reaching the Earth's surface.