Clayey landslide initiation and acceleration strongly modulated by soil swelling
Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other studies, observed pore-water pressures correlated poorly with landslide reactivation and speed. In situ and laboratory measurements strongly suggested that variable pressure along the landslide's lateral shear boundaries resulting from seasonal soil expansion and contraction modulated its reactivation and speed. Slope-stability modeling suggested that the landslide's observed behavior could be predicted by including transient swell pressure as a resistance term, whereas modeling considering only transient hydrologic conditions predicted movement 5–6 months prior to when it was observed. All clayey soils swell to some degree; hence, our findings suggest that swell pressure likely modulates motion of many landslides and should be considered to improve forecasts of clayey landslide initiation and mobility.
Citation Information
| Publication Year | 2018 |
|---|---|
| Title | Clayey landslide initiation and acceleration strongly modulated by soil swelling |
| DOI | 10.1002/2017GL076807 |
| Authors | William Schulz, Joel B. Smith, Gonghui Wang, Yao Jiang, Joshua J. Roering |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Geophysical Research Letters |
| Index ID | 70195477 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Geologic Hazards Science Center |
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