Seismic soil liquefaction refers to a significant reduction in strength and stiffness resulting from the generation of excess pore pressure under dynamic loading. It often manifests at the ground surface in the form of sand ejecta, lateral spreading or sliding, and excessive settlement due to a loss of bearing capacity. This paper focuses on the surface manifestations of seismic soil liquefaction and examines the key descriptive parameters that can be used to forecast its occurrence. Current practices often struggle to adequately link the liquefaction triggering mechanism with surface manifestation outcomes. This study proposes a framework that integrates liquefaction triggering assessment with the prediction of surface manifestation—i.e., a joint assessment of liquefaction triggering with surface manifestation. The analysis is based on an updated Standard Penetration Test (SPT) database, which also includes case histories from recent events such as the 2023 Kahramanmaraş-Türkiye Earthquakes. The results show that the liquefied and non-liquefied cases can be distinctly separated based on both triggering conditions and surface manifestation. This distinction becomes particularly apparent when considering the thickness of the non-liquefied surface layer (crust thickness) and the thickness of the critical layer across their probability of liquefaction triggering.