A Geospatial Approach for Mapping the Earthquake-Induced Liquefaction Risk at the European Scale

Francesca Bozzoni,Roberta Bonì,Claudia Meisina,Carlo G Lai,Daniele Conca,Elisa Zuccolo

doi:10.3390/geosciences11010032

Francesca Bozzoni, Roberta Bonì + Show 4 more

Open Access

https://doi.org/10.3390/geosciences11010032

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Abstract

This paper presents a geospatial methodology for zoning the earthquake-induced soil liquefaction risk at a continental scale and set-up in a Geographic Information System (GIS) environment by coupling data-driven and knowledge-driven approaches. It is worth mentioning that liquefaction is a phenomenon of soil instability occurring at a very local spatial scale; thus, the mega-zonation of liquefaction risk at a continental scale is a hard facing challenge. Since the risk from natural disasters is the convolution of hazard, vulnerability, and exposure, the liquefaction risk mapping is based on the combination of geospatial explanatory variables, available at the continental scale, of the previously listed three assumed independent random variables. First, by applying a prediction model calibrated for Europe, the probability of liquefaction is mapped for the whole continent. Then, the Analytical Hierarchy Process (AHP) is adopted to identify areas that have a high risk of liquefaction, taking into account proxy data for exposure. The maps are computed for different levels of severity of ground shaking specified by three return periods (i.e., 475, 975, and 2475 years). A broad variety of stakeholders would benefit from the outcomes of this study, such as civil protection organizations, insurance and re-insurance companies, and infrastructure operators.

Highlights

In saturated coarse-grained soil deposits, earthquakes may trigger liquefaction, a well-known phenomenon of ground fluidization and instability caused by a severe loss of shear strength and stiffness due to cyclic loading
In the proposed mega-zonation charts, the European territory is subdivided into an appropriate number of homogeneous zones defined using a sequential colour scale, ranging from low to high-risk values associated with earthquake-induced liquefaction phenomena according to a specified chromatic scale
In the proposed mega-zonation charts, the European territory is subdivided into an appropriate number of homogeneous zones defined using a sequentia3l ocfo1l3our scale, ranging from low to high-risk values associated with earthquake-induced liquefaction phenomena according to a specified chromatic scale

Summary

Introduction

In saturated coarse-grained soil deposits, earthquakes may trigger liquefaction, a well-known phenomenon of ground fluidization and instability caused by a severe loss of shear strength and stiffness due to cyclic loading. A data-driven model to predict the probability of liquefaction after an earthquake at a regional scale was calibrated by Zhu et al [2], starting from a selected number of geospatial explanatory variables adopted as proxies for ground motion intensity, soil density, and degree of saturation. In the proposed mega-zonation charts, the European territory is subdivided into an appropriate number of homogeneous zones defined using a sequential colour scale, ranging from low to high-risk values associated with earthquake-induced liquefaction phenomena according to a specified chromatic scale. In the proposed mega-zonation charts, the European territory is subdivided into an appropriate number of homogeneous zones defined using a sequentia3l ocfo1l3our scale, ranging from low to high-risk values associated with earthquake-induced liquefaction phenomena according to a specified chromatic scale. The spatial resolution of tohredechr aorfts~i1skomn .thDeeosrpditeer tohfe~1lokwml.eDveelspoifteactchuerlaocwy alenvdelreolfiaabcciluitryacoyf athnedprerelisaebniltietdy omfatphes pcorensseidnteerdinmg tahpes ecxotnresimdeerlyinlgoctahleneaxtturreemoeflythleocliaqluneaftaucrtieoonfpthheenloiqmueenfaocnti,osnucphhechnoarmtsenmoany, souffcehr scuhparptosrmt faoyr dofefceirsisounp-mpoarktefrosrindepcriisoirointi-zminagkefursrtihnerpirniovreistitziginagtiofnusrtahnedr imnvoerestdigeatatiiolends astnuddmiesorteo dasestaesilsedthsetulidquieesfatoctaiosnse-asssstohceialitqeduerfiascktifoonr-tahsesobcuiailtteednrviisrkonfomr ethnet fbouriilnt setnavnicreonatmreegniotnfoalr oinrsmtaunncieciaptarlesgciaolneasl. or municipal scales

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Findings

Discussion and Concluding