Which statement best explains why the direction of some seismic waves changes sharply as the waves travel?
Jun 20, 2009
in
Earthquake Questions
Which statement best explains why the direction of some seismic waves changes sharply as the waves travel through the Earth?
1. The Earth is spherical.
2. Seismic waves tend to travel in curved paths.
3. The temperature of the Earth's interior decreases with depth.
4. Different parts of the Earth's interior have different densities.
Like this post? Subscribe to my RSS feed and get loads more!
4 comments
Christine on June 20, 2009 at 7:05 pm
4!
jim z on June 20, 2009 at 7:05 pm
4. Densities affect the speed of propagation which causes the waves to refract (change directions).
Gwenilynd on June 20, 2009 at 7:05 pm
4!
scottsdalehigh64 on June 20, 2009 at 7:05 pm
4. The correct answer is really that different materials have different impedances to the seismic waves. When the wave is passing through a material with one impedance and it hits a new layer with a different impedance, some of the wave is reflected off of the boundary. This may be due to different densities of materials that meet each other at a clear junction layer.