  Let $M$ be a manifold with pinched negative sectional curvature. We show that
when $M$ is geometrically finite and the geodesic flow on $T^1 M$ is
topologically mixing then the set of mixing invariant measures is dense in the
set $\mathscr{M}^1(T^1M)$ of invariant probability measures. This implies that
the set of weak-mixing measures which are invariant by the geodesic flow is a
dense $G_{\delta}$ subset of $\mathscr{M}^1(T^1 M)$. We also show how to extend
these results to manifolds with cusps or with constant negative curvature.
