# Are there quanitative versions of Thurston's geometrization for manifolds which fiber over $S^1$?

The geometrization theorem tells us:

Theorem (Thurston) The mapping torus $M_\phi$ of a pseudo-Anosov diffeomorphism $\phi: S_g \rightarrow S_g$ from a genus $g$ surface to itself admits a complete hyperbolic metric of finite volume.

Otal has a complete presentation of this result starting from standard graduate material.

My question is: How much can one say about the geometry of the $M_\phi$ as a function of $\phi$ and $g$? Are there upper bounds on volume? Systole? Are there simpler bi-Lipschitz models of $M_g$? Are there any easily computable geometric quanities?

For example -- One has that the Heegaard genus of $M_g$ is $g$. This gives a lower bound on volume in terms of $g$. Is there an upper bound?

To address your last point, for a mapping torus of $S_g$, there is an upper bound on the Heegaard genus of $2g+1$, which is sharp (in fact, $M_{\phi^n}$ will have rank $2g+1$ for $n$ large), but is not always an equality. However, there is no upper bound on the volume of a fiber bundle in terms of Heegaard genus. For example, Jesse Johnson has a description of all fiber bundles of Heegaard genus 2, and it's not hard to see that these examples may have arbitrarily large volume by a Dehn filling argument.
Unfortunately in the higher genus case, there is not such a good comparison of the topological and geometric pictures. In particular, there are not many results which are uniform in the genus (although Brock's upper bound on volume in terms of pants distance has a uniform constant, but the lower bound cannot). For fixed genus, Minsky's model in principle gives a complete coarse comparison of the geometry with the topological description in terms of the action of the monodromy on the curve complex. However, the constants are not explicit, as they are obtained by geometric limit arguments. Also, there is not a strict analogue of continued fraction length; instead, one works with tight geodesics" in the curve complex, which are difficult to compute with. All this machinery was developed to resolve the ending lamination conjecture, but of course applies to the fibered case.