Seismic waves as evidence for Earth's layers

Question 1

At a seismometer, the S waves arrive 20 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km

Question 2

How do seismic waves show that the inner core is solid?

• A. P waves speed up when they enter the inner core
• B. No waves ever reach the inner core
• C. Waves get louder in the inner core
• D. S waves stop at the crust

Question 3

Inside the Earth: which statement is NOT true?

• A. S waves are longitudinal.
• B. S waves can only travel through solids.
• C. Studying seismic waves lets scientists "see" inside Earth.
• D. Earth's inner core is solid and the outer core is liquid.

Question 4

At a seismometer, the S waves arrive 15 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km

Question 5

Why do seismic waves travel in curved paths through the mantle?

• A. Earth's gravity bends them
• B. Their speed changes gradually with depth, so they refract
• C. The Moon pulls them
• D. They bounce off the surface

Question 6

Inside the Earth: which statement is NOT true?

• A. S waves can only travel through solids.
• B. Earth's inner core is solid and the outer core is liquid.
• C. Studying seismic waves lets scientists "see" inside Earth.
• D. The mantle is mostly liquid magma.

Question 7

At a seismometer, the S waves arrive 60 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km

Question 8

S waves are not detected on the opposite side of Earth from an earthquake. What does this show?

• A. The core is hollow
• B. The crust is liquid
• C. Part of the core is liquid, because S waves cannot travel through liquids
• D. S waves are faster than P waves

Question 9

Inside the Earth: which statement is NOT true?

• A. Studying seismic waves lets scientists "see" inside Earth.
• B. Earth's inner core is solid and the outer core is liquid.
• C. S waves are longitudinal.
• D. S waves can only travel through solids.

Question 10

At a seismometer, the S waves arrive 30 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km

Question 11

Which seismic waves arrive first at a seismometer?

• A. S waves (secondary, transverse)
• B. P waves (primary, longitudinal)
• C. surface waves
• D. all arrive together

Question 12

Inside the Earth: which statement is NOT true?

• A. S waves can only travel through solids.
• B. P waves can travel through solids and liquids.
• C. Studying seismic waves lets scientists "see" inside Earth.
• D. Scientists have drilled through the crust into the mantle to see the core.

Question 13

At a seismometer, the S waves arrive 15 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km

Question 14

Which seismic waves arrive first at a seismometer?

• A. P waves (primary, longitudinal)
• B. S waves (secondary, transverse)
• C. surface waves
• D. all arrive together

Question 15

Inside the Earth: which statement is NOT true?

• A. S waves can only travel through solids.
• B. Studying seismic waves lets scientists "see" inside Earth.
• C. P waves can travel through solids and liquids.
• D. The mantle is mostly liquid magma.

Question 16

At a seismometer, the S waves arrive 60 s after the P waves. Assume P waves travel at 8 km/s and S waves at 4 km/s. How far away was the earthquake, in km?

Answer km