Assessment of Liquefaction Potential during Earthquakes by Arias Intensity

TLDR

The study proposes using Arias intensity, an energy‑based measure of ground‑motion severity, to assess soil liquefaction potential during earthquakes. The method links Arias intensity values at depth to in‑situ penetration test resistance, leveraging the full seismogram’s amplitude, duration, and frequency content to evaluate liquefaction susceptibility. The approach yields a magnitude‑independent liquefaction boundary in intensity‑normalized penetration resistance space, is simple and reliable, and provides attenuation predictor equations for various site types.

Abstract

An Arias intensity approach to assess the liquefaction potential of soil deposits during earthquakes is proposed, using an energy-based measure of the severity of earthquake-shaking recorded on seismograms of the 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 magnitude-independent boundary that envelopes initial liquefaction of soil in Arias intensity-normalized penetration resistance space. The Arias intensity approach is simple to apply and has proven to be highly reliable 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 entire seismogram wave form, incorporating both the amplitude and duration elements of ground motion; all frequencies of recorded motion are considered; and Arias intensity is an appropriate measure to use when evaluating field penetration test methodologies that are inherently energy-based. Predictor equations describing the attenuation of Arias intensity as a function of earthquake magnitude and source distance are presented for rock, deep-stiff alluvium, and soft soil sites.