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Preliminary in-situ measurements of anelastic absorption in soils using a prototype earthquake simulator

Borcherdt, Roger D.; Rodgers, Peter W.

UCB/EERC-71/02, Earthquake Engineering Research Center, University of California, Berkeley, 1971-04, 14 pages (475/B65/1971)

Steady-state and transient motions were generated by a prototype earthquake simulator located in Richmond, California. The motions were recorded above the background noise throughout the foundation of the earthquake simulator and at 45 locations along a straight profile out to a distance of 620 ft. The amplitude response of the foundation is essentially flat between 12 and 35 Hz. The seismic model determined from the unreserved profile consists of a soil surface layer with an apparent shear wave velocity of 969 ft/sec, underlain by bedrock at an apparent depth of 108 feet. The average constant of proportionality for the anelastic absorption coefficient of shear waves is 2.5 multiplied by 10 superscript minus 4 sec/ft. This preliminary investigation demonstrates the feasibility for determining in-situ soil properties using the motions expected from the much larger earthquake simulator presently under construction at the site.

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