Repetitive Late Pleistocene soft‐sediment deformation by seismicity‐induced liquefaction in north‐western Lithuania

Liquefaction can cause deformation of unconsolidated sediment, but specific processes involved and the trigger mechanisms often remain obscured. This study describes multiple deformed sediment layers in a succession lacustrine sand, silt clay deposited during Marine Isotope Stage 5d north-western Lithuania. The structures (load casts, pseudonodules, ball-and-pillow structures, broken-up laminae injections) are embedded ten separate fine-grained, laterally continuous sediments. Detailed mesoscale sedimentological analyses suggest that each event consisted numerous successive stages advection facilitated by liquefaction. Low-permeability fine-grained contributed to localized pore-water pressure build-up lowering strength. Erosional top surfaces truncate with soft-sediment at least seven events were separated periods initial erosion then uninterrupted deposition lake. most likely was recurrent palaeoseismic activity possibly linked late glacial isostatic adjustment following Scandinavian Ice Sheet melting after Saalian glaciation. emphasizes potential role seismic shaping sedimentary record intraplate region north-eastern Europe contributes constraining depth liquefaction, regardless actual mechanism.