Hazard zonation mapping of earthquake-induced secondary effects using spatial multi-criteria analysis

The present study aims to suggest an approach that allows the simultaneous hazard zonation mapping of earthquake-induced secondary effects. The modeling process of the applied methodology involves an initial separate evaluation of the hazard imposed by seismically induced landslides and soil liquefaction and a subsequent stacking into one single hazard map that reflects an integrated assessment of areas exposed to both earthquake-induced phenomena under seismic shaking. To this end, we adopted a spatial multi-criteria method to support the evaluation of the controlling factors that contribute to the occurrence of coseismic landslides and soil liquefaction and we exploited the potential of Geographic Information Systems to process the various thematic layers and produce hazard zonation maps that can be used to help communities become more resilient to future coseismic hazards. The implemented methodology has the potential to categorize and discriminate regions that are threatened either by coseismic landslides, by soil liquefaction or by their combined occurrence. The results demonstrate the necessity, especially in seismically active regions which consist of mountainous terrain along with coastal plain areas and consequently imply susceptibility to slope destabilization phenomena and soil liquefaction, to jointly evaluate the hazard posed by both of these earthquake-induced secondary effects.