Term
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Definition
| The maximum stable slope angle that granular, cohesionless material can assume. For dry sand this is about 34°. |
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Term
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Definition
| A soft, plastic, light-colored clay that swells to many times its volume when placed in water. Named for outcrops near Fort Benton, Wyoming, bentonite is formed by chemical alteration of volcanic ash. |
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Term
| block glide (translational slide): |
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Definition
): A landslide in which movement occurs along a well-defined plane
surface or surfaces, such as bedding planes, foliation planes, or faults. |
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Term
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Definition
| When both rotational and translational sliding are found within one landslide mass. |
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Term
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Definition
| The imperceptibly slow downslope movement of rock and soil particles by gravity |
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Term
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Definition
| A sudden, rapid movement of a water-soil-rock mixture down a steep slope. |
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Term
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Definition
| : A moving mass of water, soil, and rock mixture. More than half of the soil and rock particles are coarser than sand, and the mass has the consistency of wet concrete |
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Term
| driving force (landslide) |
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Definition
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Term
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Definition
| The average normal force per unit area (stress) that is transmitted directly across grain- to-grain boundaries in a sediment or rock mass. |
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Term
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Definition
| The compaction of dry, low-density soils due to the heavy application of water. |
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Term
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Definition
| : The downslope movement of rock and/or soil as a semi-coherent mass on a discrete slide surface or plane (see also mass wasting). |
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Term
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Definition
| The horizontal movement on nearly level slopes of soil and mineral particles due to liquefaction of quick clays. |
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Term
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Definition
| A general term for all downslope movements of soil and rock material under the direct influence of gravity. |
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Term
| quick clay sensitive clay): |
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Definition
| A clay possessing a “house-of-cards” sedimentary structure that collapses when it is disturbed by an earthquake or other shock. |
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Term
| resisting force (landslide) |
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Definition
| Friction along the slide plane and normal forces across the plane. |
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Term
| rotational landslide (slump): |
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Definition
| ): A slope failure in which sliding occurs on a well-defined, concave-upward, curved surface, producing a backward rotation of the slide mass. |
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Term
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Definition
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Term
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Definition
| This occurs when the applied load of a structure’s foundation is greater than the bearing strength of the foundation material (soil or rock). |
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Term
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Definition
| A curved or planar surface along which a landslide moves |
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Term
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Definition
| See rotational landslide. |
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Term
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Definition
| Sinking or downward settling of the earth’s surface due to solution, compaction, withdrawal of underground fluids, or to cooling of the hot lithosphere or to loading with sediment or ice. |
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Term
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Definition
| A concave-upward fold that contains younger rocks in its core. (Contrast with anticline.) |
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Term
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Definition
| Coarse angular rock fragments lying at the base of a cliff or steep slope from which they were derived. |
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