As earthquake waves travel along the surface of the Earth, they cause the ground to move. The ground motions can be captured and displayed as a movie, providing a visual demonstration of these often indiscernible movements. Charles Ammon, a professor at Penn State University, has developed animations of earthquake waves using actual earthquake data. The visualizations show how the ground moves as seismic waves sweep across about 400 earthquake recording stations in EarthScope’s Transportable Array. These innovative visualizations have been created for selected large earthquakes that have taken place in the US and around the world.
The visualizations illustrate how seismic waves travel away from an earthquake. Because the array’s seismometers are closely spaced in a grid pattern with unprecedented density, the recorded wave amplitudes at each seismometer clearly show through time how wave after wave progresses along the great circle path from the earthquake’s epicenter.
The circles in the visualization represent earthquake recording stations and the color of each circle represents the amplitude, or height, of the earthquake wave detected by the station’s seismometer. The color of the circle changes as waves of differing amplitude travel past the seismometer. Blue represents downward ground motion, red represents upward ground motion, and darker colors indicate larger amplitudes.
There are also more videos availiable on the EarthScope Website at: http://www.earthscope.org/resources/multimedia
The IRIS Education and Outreach Program also has a wide variety of seismology related movies availiable on their website. These animations and videos explain introductory seismology concepts.
A slide show containing photos of the various USArray stations is available at: http://anf.ucsd.edu/stations/slideshow.php