An improved landslide mobility model

A relatively simple and versatile numerical model known as DAN, developed by Oldrich Hungr for the assessment of landslide mobility, has been enhanced to incorporate the consideration of a trapezoidal-shaped flow channel for more realistic modelling purposes. This enhanced debris mobility model (DMM) has been programmed to run on a spreadsheet and has been calibrated against detailed landslide data in Hong Kong. In contrast to previous work, the enhanced DMM eliminates the limitations inherited from the assumption of a rectangular flow channel with frictionless side boundaries. When using DMM, no predefined width of landslide is needed. The DMM simulates landslide mobility with the flow resistance on the whole wetted perimeter of the channel, calculates the surface width of the landslide based on the cross-sectional geometry of the channel, and is capable of predicting a lobe-shaped debris deposition area. This technical note presents details of the enhancement to the DAN formulation.Key words: landslides, debris flows, runout analysis, landslide mobility, dynamic modelling, numerical methods.