Passage VI

Earth's interior is divided into 4 primary layers of different chemical composition: the crust, mantle, outer core, and inner core. Figure 1 shows the 4 layers, their depths, and 2 named layer boundaries (Moho and Gutenberg Discontinuity). The lithosphere, asthenosphere, and transition zone boundaries were determined using speed changes in S waves, a type of earthquake wave. Speed changes indicate a phase and/or density change of material inside Earth.

Figure 2 shows how P-wave (another earthquake wave type) and S-wave velocities and density change with depth inside Earth.

Figure 3 shows how Earth's temperature changes with depth.

29. A drilling project on one of the continents struck the Moho at a depth of 60 km below the surface and a similar project on an ocean struck that boundary at a depth of 10 km beneath the ocean floor. Based on these facts and the information provided, which of the following statements about layer thickness is most accurate?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

It can be seen from figure 1 that Moho is a crust, so according to the question, Moho is 10 km below the seafloor, which means that the crust on the sea floor is thinner, so choose B