Visualizing the Ground Motions of Earthquakes: the USArray Ground Motion Visualization (GMV)

Visualizing the Ground Motions of Earthquakes: the USArray Ground Motion Visualization (GMV) Ground Motion Visualization (GMV) of the April 6, 2009 earthquake of Northern Sumatra, Indonesia.
When an earthquake occurs, the seismic waves radiate away from the source and travel in different directions and produce ground shakings that last from a few seconds to minutes. Amplitude, duration and nature of shaking at each point on the Earth’s surface depend on the size of the earthquake, distance from the source and type of seismic waves. Seismic stations record these ground motions at the station site while seismic arrays that deploy several stations within an area, sample the ground motion over an area. Deployment of dense arrays, in which array sites are closely spaced, provide an opportunity to visualize earthquake ground motions by looking at a series of snapshots that depict ground motion at individual array sites over time.
</p><p>The Transportable Array component of the USArray/EarthScope project is a rolling array of 400 broadband stations deployed on a uniform 70-km grid. This very large aperture array, along with other stations from USArray, is well suited to visualize seismic waves crossing the contiguous United States. The USArray GMV is an IRIS DMS product that illustrates how seismic waves travel away from an earthquake by depicting the recorded wave amplitudes at each seismometer location using colored circles. The color of each circle represents the amplitude of the ground motion as detected by the station's seismometer and it changes as waves of differing amplitude travel past the seismometer. Blue circles represent downward ground motion while the red circles represent upward ground motions with the darker colors indicating larger amplitudes.
</p><p>Acknowledgements: Product development within the IRIS DMS is supported by the NSF grants #EAR-0552316 and EAR-0733069.</p>


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