The researcher establishes that peat is particularly sensitive to viscous compression, and this is strongly related to the decomposition of organic material. Decomposition of organic material weakens the structure of peat, making it easier to compress. At the same time, compaction causes pores to become smaller, making less oxygen available in the pores and thus inhibiting decomposition. This means that both processes influence each other and together determine soil subsidence in the long term. Fibrous, undecomposed peat is the most compressible, but as decomposition progresses, the sensitivity to further viscous compression decreases. In addition, Van Elderen shows in his dissertation that it is important to better link different types of peat and clay to a specific parameter value in soil subsidence models: the viscous compression parameter. By dividing materials into classes, such as clay, clayey peat, fiber-rich peat, and highly decomposed peat, viscous compression can be ...