Let \(p>1\) , and let \(0<q<r<p-1<s\) be real exponents. We study a semilinear boundary value problem for the weak \(p\) -Laplacian on the Sierpiński gasket in \(\mathbb {R}^2\) , subject to Dirichlet boundary conditions. The equation involves three power-type nonlinearities and two positive parameters \(\lambda \) and \(\gamma \) . By employing variational methods, fibering maps, and a Nehari set decomposition, we prove the existence of two distinct nontrivial weak solutions for sufficiently small values of the parameters \(\lambda \) and \(\gamma \) . The critical point analysis based on the fibering-map structure provides a rigorous framework for establishing existence results in the context of non-smooth fractal domains. This work contributes to the study of nonlinear elliptic equations in fractal settings.