Discussion of Daniels and McCusker (2010): “Operator bias characterizing stream substrates using Wolman pebble counts with a standard measurement template.” Geomorphology 115, 194–198

This technical note presents a new technique for addressing limited displacement monitoring data for active landslides. Subsurface geomorphology, where data are available, is characterized via a numerical integration tool into a dynamic geometric parameter, and extrapolated using regression analysis. Error analysis shows that the numerical integration can be implemented successfully using only a relatively few number of integration points. When applied to a real, large-scale landslide example from the literature, the technique is able to simulate ground-truth conditions reasonably with an error of approximately 1.4%. The implications of this technical note are that it is possible to overcome limitations in landslide studies at sites with scarce data using available surface displacements and calculated subsurface geometries.