A generalised severity number to predict liquefaction damage with lateral spreading

Abstract

This study introduces a generalization of the classical one-dimensional liquefaction severity indexes to extend their predictive capability for the occurrence of lateral spreading. After a critical overview of the most used indexes, the rationale for extension to bidimensional conditions determined by non-horizontal geomorphology is presented together with the rule to achieve generalization. The efficacy of the new index is demonstrated with a performance based study on two cases, the earthquakes of May 20th 2012 (Mw 6.1) at Terre del Reno (Emilia-Romagna, Italy) and of February 11th 2011 (Mw=6.2) at Christchurch (New Zealand). Stratigraphic attributes including thickness, depth, composition and relative density the liquefiable layers, obtained over the whole territories from rich datasets of Cone Penetration Tests (CPT) are coupled with topographic information derived from the digital elevation model to provide the input for the analysis. Consistency assessment and spatial interpolation of data are carried out with geostatistical tools implemented in a GIS platform. Validation versus post-earthquake damage survey, quantified with a binary classification method, shows the paramount role of the bidimensional conditions.

Regional scale probabilistic procedure for estimating lateral spread displacements

“…The linear DWF is similar to that employed in the calculation of LPI, but the linear DWF used to calculate LPI is linear to 20 m and not 15 m. DWF 1 and DWF 2 place more weight on liquefied layers near the ground surface compared to the linear DWF, and apply zero weight on liquefiable layers below 12 m and 15 m, respectively. DWF 3 is similar to that recommended independently by Paolella et al [8]. The intent of DWF 3 is to place most weight on the upper 7 m of the soil profile and little weight to soil below a depth of 12 m with a sharp transition.…”

“…A recent paper by Paolella et al [8] proposed a unitless, generalized liquefaction severity number (GLSN) to estimate liquefaction severity at regional scales. Their method calculates a modified LDI with a newly proposed depth weighting factor which uses the inverse tangent function.…”

PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia-Romagna, Italy)

“…As widely reported in the bibliography, the propagation of seismic waves through the upper portion of the soil can be modified by local site conditions (i.e., Bozzano et al, 2017;Fabozzi et al, 2021;Falcone et al, 2020Falcone et al, , 2021Gautam, 2017;Luo et al, 2020;Meza-Fajardo et al, 2019) and can determine the triggering of earthquakeinduced effects at ground surface (i.e., Forte et al, 2021;Martino et al, 2017Martino et al, , 2019Giannini et al, 2022;Paolella et al, 2022). In Terre del Reno, these earthquakes triggered several earthquake-induced effects (Chini et al, 2015;Papathanassiou et al, 2015), among which linear and punctual liquefaction effects were the most prominent.…”

“…Several authors (i.e., Ecemis, 2021;Jain et al, 2022) have highlighted that the presence of a tiny alternation of silt and sand seems to influence the liquefaction occurrence, while other studies focused on the role of silty sands and soil packing condition on liquefaction triggering (i.e., Naeini and Baziar, 2004;Stamatopoulos, 2010;Gobbi et al, 2022a). To overcome the difficulties related to heterogeneously complex soil conditions, integrated approaches are applied to predict the occurrence of liquefaction by combination of numerical and experimental methods (Gobbi et al, 2022b;Rios et al, 2022;Paolella et al, 2022). Further steps toward this direction were made for the Terre del Reno case study by pursuing two main objectives of the PERL project in order to (i) define a new integrated methodology to assess the liquefaction susceptibility in complex stratigraphic settings through a multi-level approach and (ii) perform the seismic microzonation of the municipality for land and civil protection planning purposes.…”

Brief communication: PERL: a dataset of geotechnical, geophysical, and hydrogeological parameters for earthquake-induced hazards assessment in Terre del Reno (Emilia Romagna, Italy)

“…Two main shocks were recorded during the crisis: the first one on 20th May with ML 5.9 and epicenter in Finale Emilia (Modena Province), and the second one on 29th May with ML 5.8 and epicenter in Medolla (Modena Province). These events triggered several earthquake-induced effects (Chini et al, 2015, Papathanassiou et al, 2015, Paolella et al 2022, among which linear and punctual liquefaction effects were the most prominent. Such effects are related to the complex sedimentological and stratigraphic setting of the ares (i.e.…”