NEES Shake Table Laboratories

No two earthquakes are exactly alike. During an earthquake, the ground does not move just back-and- forth or up-and-down, but may react in an undulating wave, a brief sharp shake, or as a tremor that builds and recedes. The strength of an earthquake varies as well, depending on the amount of stress to be released and if it starts deep in the earth's crust or closer to the surface.

A shake table is designed to recreate both the movements of the ground and the varied forces generated by earthquakes. It is an invaluable testing tool for the simulation of earthquakes in a laboratory. A shake table typically has five degrees of freedom, meaning it can move in five separate directions. The table can move horizontally and vertically, roll back and forth, rock from side to side, and twist on a central axis.

A computer system controls the motion of the table. This allows researchers to select from more than one thousand earthquake records in order to simulate the vibrations of actual past earthquakes. Researchers can "create their own" earthquakes as well, including levels beyond the Richter scale.

The NEES program has three equipment sites with shake tables that have been upgraded or newly constructed. The University of Nevada at Reno has three bi-axial shake tables, which can function in unison or independently. Two relocatable shake tables at the University of Buffalo, SUNY may be moved up to 100 feet apart. The University of California at San Diego's outdoor shake table is the largest in the US. These three sites represent the best testing facilities of their kind

Video of the UCSD Shake Table


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