Valid debris-flow models must avoid hot starts
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- Data Release: USGS data release - Debris-flow video files, Chalk Cliffs, Colorado, USA, 2017
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Abstract
Debris-flow experiments and models commonly use “hot-start” initial conditions in which downslope motion begins when a large force imbalance is abruptly imposed. By contrast, initiation of natural debris flows almost invariably results from small perturbations of static force balances that apply to debris masses poised in steep channels or on steep slopes. Models that neglect these static balances may violate physical law. Here we assess how the effects of hot starts are manifested in physical experiments, analytical dam-break models, and numerical models in which frictional resistance is too small to satisfy static force balances in debris-flow source areas. We then outline a numerical modeling framework that avoids use of hot starts. In this framework an initial static force balance is gradually perturbed by increasing pore-fluid pressure that may trigger the onset of debris motion. Subsequent increases in pore-fluid pressure, driven by debris motion, may then reduce the debris frictional strength, leading to high flow mobility.
Suggested Citation
Iverson, R.M., George, D.L., 2019, Valid debris-flow models must avoid hot starts, in 7th International Conference on Debris-Flow Hazards Mitigation-Proceedings, Golden, CO, June 10-13, 2019, p. 25-32, https://doi.org/10.25676/11124/173051.
| Publication type | Conference Paper |
|---|---|
| Publication Subtype | Conference Paper |
| Title | Valid debris-flow models must avoid hot starts |
| DOI | 10.25676/11124/173051 |
| Year Published | 2019 |
| Language | English |
| Publisher | Association of Environmental and Engineering Geologists (AEG) |
| Contributing office(s) | Volcano Science Center |
| Description | 8 p. |
| Larger Work Type | Book |
| Larger Work Subtype | Conference publication |
| Larger Work Title | 7th International Conference on Debris-Flow Hazards Mitigation-Proceedings |
| First page | 25 |
| Last page | 32 |
| Conference Title | Seventh International Conference on Debris-Flow Hazards Mitigation |
| Conference Location | Golden, CO |
| Conference Date | June 10-13, 2019 |