Decreasing the ground resistance of a grounding system in high resistivity soil is often a formidable task. A new method is proposed to decrease ground resistances. This method requires three steps: (1) drilling deep holes in the ground; (2) developing cracks in the soil by means of explosions in the holes; and (3) filling the holes with low resistivity materials (LRM) under pressure. Most of the cracks around the vertical conductors will be filled with LRM and a complex network of low resistivity tree-like cracks linked to the substation grid is formed. The principle of decreasing ground resistances using this new method is described and the effectiveness of the new method is examined. Application of this method to power system grounding is presented together with measurement results.