Michael J. Randall Hans F. Schwaiger Roger P. Denlinger Larry G. Mastin 2013 <p>Ash3d is a three-dimensional Eulerian atmospheric model for tephra transport, dispersal, and deposition to study and forecast hazards of volcanic ash clouds and tephra fall. In this report, we explain how to set up simulations using a web interface, and how to view and interpret model output. We also summarize the architecture of the model and some of its properties.</p> application/pdf 10.3133/ofr20131122 en U.S. Geological Survey User’s guide and reference to Ash3d—A three-dimensional model for Eulerian atmospheric tephra transport and deposition reports