This diagram shows the changes in c-axis azimuths with increasing shear strain. Note that all grains with c-axis azimuths smaller than 160° tend to rotate towards orientations with a smaller azimuth.

The azimuth ranges 0-45° and 160-180° comprise flat curves indicating low azimuth rotation rates whereas the azimuth range 45-160° reflects high azimuth rotation rates.

The survival potential of grains in strain history seems to be related to the  c-axis azimuth rotation behavior: grains with low c-axis rotation rates survive over a longer periods than those grains with high c-axis rotation rates.