EQ+Animations

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media type="file" key="amplification.swf" width="344" height="258" align="center" = =

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=Amplification = ** Shaking levels at a site may be increased, or amplified, by focusing of seismic energy caused by the geometry of the sediment velocity structure, such as basin subsurface topography, or by surface topography ** **. **



media type="file" key="attenuation.swf" width="432" height="324" align="center"

= = =Attenuation = **When you throw a pebble in a pond, it makes waves on the surface that move out from the place where the pebble entered the water. The waves are largest where they are formed and gradually get smaller as they move away. This decrease in size, or amplitude of the waves is called attenuation. Seismic waves also become attenuated as they move away from the earthquake source**