D-Claw: a granular-fluid model for landslides, debris flows, and their interactions with water bodies.

Abstract

D-Claw is a depth-averaged, two-phase, mathematical model originally developed for dense granular flows, such as landslides and debris flows (Iverson & George, 2014). A key property of the model is the incorporation of granular dilatancy, which regulates the coupled evolution of solid-volume fractions and pore-fluid pressure and thereby mediates flow resistance. Model properties were motivated by our desire to simulate landslide initiation and resolve the evolving downslope mobility based on theoretically quantifiable sediment material properties, rather than utilize artificial rheological rules that predetermine mobility and require unrealistic initial force balances. More recently, by utilizing D-Claw's solid-fluid evolution, we have extended it to hybrid problems that involve the interaction of granular material and water bodies (e.g., landslide-generated tsunamis, dam breaching, and erosion).

D-Claw is implemented in the open-source software framework of Clawpack (clawpack.org), and employs algorithms that facilitate the computation of large-scale problems (e.g., AMR, dynamic DEM integration), similar to the related tsunami modeling software, GeoClaw (George, 2006). I will describe key aspects of the D-Claw mathematical model and present some recent hybrid applications that utilize the software for hazard assessment.

BIO

David George received his Ph.D. in Applied Mathematics from the University of Washington, Seattle, in 2006. His research has been focused on the development of numerical methods and open-source software for wave-propagation problems and PDEs. In his graduate work, he focused on problems related to tsunami modeling. After postdoctoral positions in Mathematics at The University of Utah and the University of Washington, he became a Mendenhall postdoctoral fellow, and later, a permanent staff scientist at the USGS' Cascades Volcano Observatory in Vancouver, Washington. At the USGS, George develops models and software for shallow earth-surface flows such as landslides, debris flows, tsunamis, and related problems.