Lyapunov eponents and strong exponential tails for some contact Anosov flows

For the time-one map $f$ of a contact Anosov flow on a compact Riemann manifold $M$, satisfying a certain regularity condition, we show that given a Gibbs measure on $M$, a sufficiently large Pesin regular set $P_0$ and an arbitrary $\delta \in (0,1)$, there exist positive constants $C$ and $c$ such that for any integer $n\ge 1$, the measure of the set of those $x\in M$ with $f^k(x)\mathrm{\notin }{P}_0$ for at least $\delta n$ values of $k=0,1,\dots ,n-1$ does not exceed $C{e}^{-cn}$.