Mineralogical imprints of earthquake activity in sedimentary structures

Seismic activity can leave distinct imprints in sediments; however, the geochemical and mineralogical conditions controlling sediment liquefaction and deformation remain incompletely understood. Here, we present a comprehensive study combining laboratory experiments and field samples to investigate the formation of seismically-induced structures, with a particular focus on sideritic and core-rim features. Core-rim structures (CRS) were consistently identified across all experimental and field conditions subjected to shocks, independent of the degree of water mineralization, the presence of iron compounds, or experimental duration. The observations suggest that their formation is largely controlled by physical processes during seismic events, indicating that CRS may represent a potentially indicator of seismic activity in unconsolidated sediments. Additionally, variations in their morphology and elemental distribution appear to reflect fluid flow pathways, providing insights into fluid redistribution during seismic deformation in the field. Sideritic structures, observed exclusively in field samples and laboratory variants with FeO(OH), displayed ring-like morphologies and were primarily composed of FeO and carbonate minerals. Multivariate statistical analyses, including cluster and principal component analysis (PCA), revealed strong similarities between these environments, pointingto comparable geochemical conditions during their formation. Overall, this studydemonstrates the value of integrating experimental and field-based approachesto improve our understanding of seismic deformation processes. Core-rim and sideritic structuresmay contribute useful evidencefor interpreting past seismic events and for refining criteriaused to identify seismites and reconstruct fluid migration patterns in sedimentary systems.