The equation for the axis of symmetry of a parabola in the vertex form \( y = a(x - h)^2 + k \) is given by the line \( x = h \), where \((h, k)\) is the vertex of the parabola.
For the given equation \( y = 3(x - 1)^2 - 12 \):
- The value of \( h \) (from \( (x - h) \)) is 1.
- Therefore, the equation of the axis of symmetry is:
\[ x = 1 \]