ASSESSMENT OF LIQUEFACTION POTENTIAL DURING EARTHQUAKES BY ARIAS INTENSITY

An Arias intensity approach to assess the liquefaction potential of so il deposits during earthquakes is proposed, using an energy-based meas ure of the severity of earthquake-shaking recorded on seismograms of t he two horizontal components of ground motion. Values representing the severity of strong motion at depth in the soil column are associated with the liquefaction resistance of that layer, as measured by in situ penetration testing (SPT, CPT). This association results in a magnitu de-independent boundary that envelopes initial liquefaction of soil in Arias intensity-normalized penetration resistance space. The Arias in tensity approach is simple to apply and has proven to be highly reliab le in assessing liquefaction potential. The advantages of using Arias intensity as a measure of earthquake-shaking severity in liquefaction assessment are: Arias intensity is derived from integration of the ent ire seismogram wave form, incorporating both the amplitude and duratio n elements of ground motion; all frequencies of recorded motion are co nsidered; and Arias intensity is an appropriate measure to use when ev aluating field penetration test methodologies that are inherently ener gy-based. Predictor equations describing the attenuation of Arias inte nsity as a function of earthquake magnitude and source distance are pr esented for rock, deep-stiff alluvium, and soft soil sites.