Determining the rheologic properties of coarse- grained mass flows is an important step to mathematically simulate potential inundation zones. Using the vertically rotating flume designed and built by the U.S. Geological Survey, laboratory procedures and subsequent data reduction have been developed to estimate shear stresses and strain rates of various flow materials. Although direct measurement of shear stress and strain rate currently (1992) are not possible in the vertically rotating flume, methods were derived to estimate these values from measurements of flow geometry, surface velocity, and flume velocity.