Paleo-dammed lake sediments in the upper reaches of the Minjiang River and its tributaries show several types of deformational structures that are interpreted as seismites. In this paper, the authors analyze the types and characteristics of these deformations. The authors classify the structures into two types: the small-scale deformations, which are related to the plastic deformation, liquefaction and fluidization processes of the soft sediment. Another is the large-scale folds formed by the disturbance of the collapse masses (slip block).The comparison with other soft-sediment deformation structures and study of the seismotectonic environment indicate that the main trigger factors for deformation were seismic shocks, collapse and landslide induced by the earthquake.