TeXes Science Practice Test

What type of seismic waves create the largest ground movements?

1. Primary waves

2. Secondary waves

3. Tertiary waves

4. Surface waves

The correct answer is: Surface waves

Surface waves create the largest ground movements during an earthquake due to their unique characteristics and the way they propagate through the Earth's crust. These waves travel along the surface of the Earth and are responsible for the shaking and rolling motion that is often felt during significant seismic events. Unlike primary waves, which are compressional and travel through solids, liquids, and gases, and secondary waves, which are shear waves that only move through solids, surface waves are more complicated and tend to remain confined to the outer layer of the Earth. This confinement means that as they travel, they can cause significant horizontal and vertical ground displacement, leading to more intense shaking at the surface. The energy released during an earthquake is concentrated in these surface waves as they arrive after the primary and secondary waves, often resulting in the greatest amplitude and longer duration of ground movement. Therefore, understanding the nature of surface waves is crucial in assessing the impact of earthquakes on structures and landscapes.