Offshore energy production increases rapidly on the Finnish west coast. Effective ground investigation methods are needed for offshore wind farm construction and cable route planning. This study identified fine-grained local subsurface sediment units based on seismoacoustic survey and sediment coring complemented with geotechnical properties from free fall cone penetrometer tests. The finegrained sediments in the study area consist of brackish-water mud, postglacial lacustrine clay and glaciolacustrine clay and silt which all show variability in physical properties and undrained shear strength profile. The study shows that free fall penetrometer tests provide a ground-truth for the seismoacoustic profile interpretation and, combined with seismoacoustic survey and sediment coring enable a fast and cost-efficient site reconnaissance.@en

The paper shows a moving least squares reconstruction technique applied to the B-spline Material Point Method (B-spline MPM). It has been shown previously that B-spline MPM can reduce grid-crossing errors inherent in the original Material Point Method. However, in the large deformation regime where the gridcrossing occurs more frequently, the convergence rate of B-spline MPMis lower. In this paper, moving least squares reconstruction is employed to retrieve the expected convergence rate. The proposed improvement is examined in terms of the spatial convergence using the methods of manufactured solutions for large deformations.@en