How do earthquakes reveal secrets of Earth’s interior?

Resources

Background
Activities
     • Earth's Interior Structure
Vocabulary
Related Animations
     • Refraction
     • Multi station Seismic Network
     • Travel-time Curves

Seismic Tomography

  • For background on this animation series, download Background from the Resources box.

  • Animations are available for preview in embedded YouTube.

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Tomography

In this animation we simplify things and make an Earth of uniform density (isotropic; constant velocity sphere) with a slow zone that we image as a magma chamber for simplicity. For reference, the Earth figures below show the difference between our simple animation and a body with changes in rock type and temperature that cause the seismic waves to refract and bend when transmitted between different rock compositions.

Quicktime (3.1 MB)

Animación Quicktime (3 MB)

A CAT (computed axial tomography) scan animation is included because seismic tomography is often compared to CAT scans. Both techniques have an energy source (seismic tomography uses the energy generated from earthquakes; CAT scans use x-ray energy) and a receiver (seismic tomography uses seismograph stations; CAT scans use comtuters) that records the data. For more, see CAT scans & seismic tomography below.

Quicktime (2.1 MB)

Animación Quicktime (2.1 MB)

Animations and videos are made in partnership with Earthscope, USGS, and Volcano Video & Graphics.

Please send feedback to Jenda Johnson.