Science Quiz on Seismic Waves

A global earthquake monitoring system records a shadow zone where no S-waves are detected. What does this most directly support about Earth's interior structure?

• The mantle is partially solid.

• The outer core is liquid and absorbs S-waves.

• The outer core is liquid and refracts P-waves

• The inner core has different density than the crust

In a simulation, seismic waves travel through different Earth materials. In which scenario is wave speed the greatest, and why?

• Through air, due to lower resistance

• Through water, due to fluid cohesion

• Through solid mantle rock, due to particle rigidity

• Through molten rock, because of higher temperature

A mining company uses artificial seismic waves to map underground structures. What should they analyze to best locate a dense mineral deposit?

• The delay in S-wave arrival

• The increase in wave amplitude

• The difference between crustal thickness

• The reflection and refraction patterns of P-waves

Why might two locations equidistant from an epicenter experience different durations of shaking?

• The Richter scale varies based on location.

• The energy is uniformly released in all directions.

• The Earth's rotation disperses wave energy unevenly.

• Seismic waves are affected by local geology and materials.

What is the primary difference between P-waves and S-waves?

• P-waves and S-waves are identical in their properties.

• P-waves are faster and travel through gases; S-waves are slower and only travel through solids.

• P-waves are slower and only travel through solids; S-waves are faster and travel through solids and liquids.

• P-waves are faster and travel through solids and liquids; S-waves are slower and only travel through solids.

Why do S-waves do not travel through the outer core of the Earth?

• The outer core is liquid.

• S-waves are absorbed by all metals.

• The outer core is too dense.

• The outer core reflects all seismic waves.

A geophysicist suggests using the travel-time difference between P-waves and S-waves to estimate epicenter distance. Which reasoning BEST justifies this method?

• S-waves arrive faster than P-waves

• Surface waves distort subsurface wave records

• P- and S-waves have the same speed in all layers

• The difference in arrival times increases with distance

Geologists have observed that seismic waves travel faster through some parts of the Earth than others. What can be inferred if seismic P-waves suddenly speed up at a depth of 2,900 km?

• They are entering a hotter region.

• They are transitioning into a less dense layer.

• They are entering the solid inner core.

• They are passing from liquid to solid material.

Which of the following elements are the main composition of Earth's inner core?

• magnesium and silicon

• silicon and oxygen

• nickel and iron

• oxygen and iron

Which type of body wave has a side-to-side or horizontal motion that can cause buildings to sway during an earthquake?

• P-waves

• S-waves

• Surface waves

• Love waves