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22-24. Simulation of granular fluids for cascading hazard investigation

Simulation of the movement of granular fluids over complex terrain is a core tool for assessing a wide range of geophysical hazards, from the growth and runout of postfire debris flows to the generation of landslide displacement waves. We seek a Mendenhall to advance the theory, numerics, software, validation, or application of granular fluid modeling in service of hazard assessment. 

Description of the Research Opportunity

Many geophysical hazards can be idealized as the flow of, or interaction between, granular-fluid mixtures and water. Examples include but are not limited to: the runout of landslides, the generation of landslide tsunamis, the recruitment of sediment into surface overland flow or tsunamis, the breaching of earthen dams, and the routing of erosive outburst floods. Tools that enable simulation of granular fluids over complex terrain have a wide range of applications for hazard assessment. 

We seek a Mendenhall fellow to advance the understanding of simulation of granular fluids. A successful candidate is expected to undertake research that contributes to one or more of the following general topic areas: fundamental physical processes, algorithm design and numerics, software development, benchmark development and validation, or hazard assessment applications. The fellow may work on a project with relevance to many hazards (e.g., representing segregation feedbacks) or on a project focused on a particular hazard (e.g., landslide tsunamis, outburst floods, postfire debris flow sediment recruitment). Research in all areas may benefit from the existing set of experiments conducted at the U.S. Geological Survey debris flow flume (Logan, Iverson, and Obryk, 2018). Some examples of each of the main topic areas follow. 

Fundamental advances: One possible area of research regards the fundamental physical processes that describe the interaction between grains and water. Research in this area may include the enhancement of existing mathematical models (e.g., the D-Claw model, George and Iverson, 2014; Iverson and George, 2014) or development of new physical-process models. It may also focus on the representation of specific physical processes, such as entrainment and deposition of sediment, the segregation of different grain types, and the dewatering of granular flows. 

Model implementation, verification, and validation: Another area of research is that of model implementation. Research in this area may include generation of benchmark tests for model validation and verification, including comparison between depth averaged and fully three-dimensional models. It may also include enhancements to software usage and performance.  

Applications: A final area of research is in the development of applications to specific geologic hazards. Research topics in this area may include erosion and deposition of landslides or debris flows; the generation of displacement waves by landslides or volcanic processes; or the formation and breaching of landslide dams and associated outburst floods.  

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas. 



George, D.L., and Iverson, R.M., 2014, A depth-averaged debris-flow model that includes the effects of evolving dilatancy. II. Numerical predictions and experimental tests: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, v. 470, no. 2170, p. 20130820., doi: 10.1098/rspa.2013.0820

Iverson, R.M., and George, D.L., 2014, A depth-averaged debris-flow model that includes the effects of evolving dilatancy. I. Physical basis: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, v. 470, no. 2170, p. 20130819., doi: 10.1098/rspa.2013.0819

Logan, M., Iverson, R.M., and Obryk, M.K., 2018, Video documentation of experiments at the USGS debris-flow flume 1992–2017 (ver 1.4, January 2018): U.S. Geological Survey Open-File Report 2007–1315,


Proposed Duty Station(s)

Golden, Colorado

Vancouver, Washington 


Areas of PhD

Geology, geomorphology, geophysics, hydrology, hydrometeorology, engineering geology or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered). 



Applicants must meet one of the following qualifications: Research Geologist, Research Hydrologist, Research Physical Scientist, Research Mathematician, Research Physicist, Research Engineer, Research Civil Engineer 

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)