The liquefaction potential of a soil deposit is an important aspect to consider the stability of structure due to the earthquake. The liquefaction may also contribute to the safety of coastal constructions. The assessment of liquefaction potential can be started by having the physical properties of sandy soil that include grain size and density. Those parameters had known to give effects to the liquefaction resistance. Those physical properties of sand soil associated with liquefaction resistance must be tested in the laboratory. A case study of a real construction design in Padang, Indonesia is discussed here. The liquefaction potential was assessed using the Density-Grain size methods. The suggested solution to treat those problems is then provided. The compaction treatment to reach a certain relative density before the construction on site may avoid the liquefaction potential and save the coastal structure. Show More