  We study the evolution of magnetic shear angle in a flare productive active
region NOAA 10930. The magnetic shear angle is defined as the deviation in the
orientation of the observed magnetic field vector with respect to the potential
field vector. The shear angle is measured in horizontal as well as vertical
plane. The former is computed by taking the difference between the azimuth
angles of the observed and potential field and is called the twist-shear, while
the latter is computed by taking the difference between the inclination angles
of the observed and potential field and is called the dip-shear. The evolution
of the two shear angles is then tracked over a small region located over the
sheared penumbra of the delta sunspot in NOAA 10930. We find that, while the
twist-shear shows an increasing trend after the flare the dip-shear shows a
significant drop after the flare.
