a1 Department of Mathematics, University of California, Berkeley, CA 94720, USA
The Bowen-Margulis measure on the unit tangent bundle of the universal covering of a compact manifold of negative curvature is determined by its restriction to the leaves of the strong unstable foliation. We describe this restriction to any strong unstable manifold W as a spherical measure with respect to a natural distance on W.
(Received July 22 1987)
(Revised May 05 1988)