Seed bank is an important determinant of vegetation dynamics, particularly in disturbed ecosystems. Disturbance like volcanic eruptions largely alter landscapes influencing plant succession and ecosystem recovery. Thus, to predict regeneration potential of such ecosystems, it is important to have a clear understanding of seed bank dynamics as well as its relationship to the aboveground vegetation. This study investigated seed bank at Mount Usu, Japan, following eruptions in 1977-78 and 2000. It compared seed bank composition with aboveground vegetation across four sites: crater grassland (GL), foot grassland (FGL), natural forest (NF) and artificial forest (AF). To determine seed bank composition, a total of 295 soil samples (volume 100-cm³), were collected in autumn 2023 and spring 2024, with half of the autumn samples undergoing cold stratification treatment (2-4°C) for two months. Aboveground vegetation was surveyed in summer 2024. Germination method was performed in a greenhouse to examine seed bank. Kruskal Wallis tests were performed to examine the dynamics of seed bank in species richness and seedling density between seasons and between treatments. A total of 138 species (30 families) were found with 117 and 59 species aboveground and in seed bank respectively. The highest similarity in species composition between seed bank and aboveground was found in GL (46%) with the lowest in AF (10%). GL had the highest density with 3550 seedlings/m² in average, followed by FGL, NF and AF with 2073, 1131, and 694 seedlings/m² respectively. The effect of seasons and cold stratification was not significant on seed density and species richness within site. While most of the species aboveground was native to Japan, nearly half (48%) of the species in the seed bank was nonnative. Perennial life-form, and Asteraceae and Poaceae families were dominant throughout. Variations in species richness and density, with grasslands exhibiting higher densities and richness than forests, suggest that habitat type may influence regeneration. Seed bank persistence, reflected by the lack of seasonal and cold stratification effects, and the dissimilarity between seed bank and vegetation, could be due to dormancy strategies of different species, suggesting seed bank as a vital source for future. Besides, the presence of nonnative species in the seed bank indicates alteration of vegetation composition. Thus, these findings contribute to interpret successional trajectories in disturbed ecosystems as well as revealing potential deterioration of the natural ecosystem of Mount Usu by nonnative species.