It is generally accepted that seismic vibrations caused by explosive detonation propagate in a circular manner around the vibration source. Currently, peak vibration velocity (PPV) measurements of the horizontal components of seismic vibration in the X direction (PPVx) and in the Y direction (PPVy) are performed at different directional angles, assuming that their values are constant regardless of the directional angle of measurement ‘α’.Seismic velocity values measured in the X direction are denoted by the subscript ‘x’ and in the Y direction by the subscript ‘y’. The aim of this paper was to demonstrate the effect of the directional angle of vibration velocity measurement ‘α’ on the maximum value of the horizontal components PPVx and PPVy. The methodology used involved the implementation of a Cartesian triaxial reference system, in which the horizontal Y axis coincides with the direction of the line of blast holes and the X axis is perpendicular to it. This configuration made it possible to define the directional angle ‘a’ of the vibration velocity measurement with respect to the reference system. A theoretical analysis of the distribution of the resultant circular vibration velocity into two components, Vx and Vy, was carried out. The values of the horizontal radial components in the X direction and the tangential components in the Y direction were then calculated using the directional measurement angle ‘α’. Theoretical analysis and measurement results showed that the PPVx and PPVy velocities at a fixed distance from the vibration source depend on the value of the directional angle ‘α’ of the velocity measurements. Particle vibration velocity measurements of the medium PPVx, PPVy at any measurement angle ‘α’ can be quickly converted in the X direction to the maximum particle vibration velocity PPVx max for a directional angle of 90°, and in the Y direction to the maximum particle vibration velocity PPVy max for a directional angle of 0° based on the equations given in the article. The values of PPVx max, PPVy max used to assess the harmfulness of seismic vibrations acting on buildings should not exceed the safe values read from the Polish Standard.