We track solution reliability by using a quality flag.
'A' identifies full compliance to all criteria, and the 'B', 'c', 'D' letters correspond to decreasing levels of quality.
B flag is given to those moment tensors that have a difference between preliminary and final coordinates greater than 0.3 degree and lower than 0.5 degree.
If this difference is greater than 0.5, the coordinates are kept fixed along the inversions and the flag becomes C. Usually these coordinates variation are due to a low quality of azimuthal distribution of stations.
Flag D is given only when the resulting moment tensor has a high no-double-component due to low signal-to-noise ratio.