Liquefaction is considered to be a phenomenon in whichrigid and soils lose their strenght for a short period of time during an earthquake. The occurrence of soil liquefaction is one of the problems which occurs in water saturated soils and in areas where earthquakes are more frequent. An important step in detecting areas susceptible to liquefaction is the assessment of the liquefaction potential, i.e. the assessment of the possibility of liquefaction. The standard penetration test (SPT) and the static penetration test (CPT) are mostly used to assess the liquefaction potential. In order to prevent the occurrence of liquefaction, appropriate techniques for improving soil properties are undertaken. By using a deep dynamic compaction technique or a vibrating technique, in which a suitable deep vibrator is applied, we try to compact soil particles is such a way as to reduce pore volumes. Penetration of a vibrator into soil is facilitated by compressed air or jet of water, which additionally activate soil particles to become more compact. The moved particles become more solid and shear strenght is higher as well as the degree of compaction.