The focal mechanism or the fault plane solution describes the orientation of the fault and the slip on the fault relative to a geographical coordinate system. The focal mechanism is the most important parameter to determine once the location and magnitude are known and it is used to determine the actual geometry of the faults as well as inferring the style of faulting and stress regimes of a particular region. All seismological methods of determining fault plane solutions are based on the radiation pattern (see below) that the seismic earthquake source sends out. Seismic waves have different amplitudes and polarities in different directions depending on the relative position of the source with respect to a seismic station.