The given equation of the parabola is:
\[ y = 3(x - 1)^2 - 12 \]
This equation is in vertex form, which is:
\[ y = a(x - h)^2 + k \]
where \((h, k)\) is the vertex of the parabola. In your equation, we can identify:
- \(h = 1\)
- \(k = -12\)
The axis of symmetry of a parabola in vertex form is given by the line \(x = h\).
Thus, for this parabola, the axis of symmetry is:
\[ x = 1 \]