Experimental evidence for shallow, slow‐moving landslides activated by a decrease in ground temperature. Issue 13 (8th July 2016)

• Record Type: Journal Article
• Authors: Shibasaki, Tatsuya; Matsuura, Sumio; Okamoto, Takashi
• Is Part Of: Geophysical research letters. Volume 43:Issue 13(2016)
• Page Start: 6975
• Page End: 6984
• Publication Date: 2016-07-08
• Subjects: ground temperature -- smectite -- landslide; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL069604
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: In order to understand the trigger mechanism of slow‐moving landslides occurring in the early cold season from late autumn to winter, we investigated the effect of temperature on the shear strength of slip surface soils. Displacement‐controlled and shear stress‐controlled box shear experiments were performed on undisturbed slip zone soils under residual strength conditions. Test results conducted at temperatures from 9 to 25°C showed remarkable shear strength reductions with decreasing temperature. Creep‐like slow shear displacements were induced by a decrease in temperature. These temperature‐dependent shear behaviors are attributed to the rheological properties of hydrous smectite that dominantly compose the soil material along the failure surface. Our experimental results imply that ground temperature conditions influence slope instability, especially for shallow landslides occurring in smectite‐bearing rock areas. Key Points: Some shallow, slow‐moving landslides become active on gentle clayey slopes early in the cold season A decrease in temperature weakens smectite‐rich, shear zone soils and triggers slow shear displacement Seasonal decreases in ground temperature can induce slope instability