Correlation Analysis between the Number of Cycles and Duration of Large-Magnitude Earthquakes in Chile and Japan Regions

The number of cycles of earthquakes is an important factor in simplified assessment methods of the liquefaction potential of soil. Herein, a set of correlations was obtained for several definitions of the number of cycles by peak counting (NP) and duration of large-magnitude earthquakes to verify whether the duration can be used as an indirect measure of the number of cycles for assessing the soil liquefaction potential. Additionally, a novel criterion for bracketed significant duration (DBS) estimation was suggested based on intervals of cumulative absolute displacement (CAD). The most strongly positive correlations between the number of cycles and duration definitions were obtained for NP and bracketed duration (DB) based on absolute thresholds rather than relative thresholds, suggesting that absolute thresholds are more appropriate for liquefaction potential assessment. While duration is an important factor for understanding the behaviour of the number of cycles of large-magnitude earthquakes, it does not provide a comprehensive explanation. To reduce the dispersion in the correlations, additional parameters, such as frequency content, should be incorporated in the analysis.