Lithosphere Lithosphere: The lithosphere comprises the Earth’s crust as well as part of the upper mantle. In fact, the lithosphere is approximately 100 kilometers thick and is relatively strong as compared to the underlying asthenosphere.

Perched Groundwater Perched Groundwater – In geology, “perched groundwater” refers to unconfined groundwater which separates from an underlying body of groundwater by an unsaturated zone or vadose zone.

“Toe” of a Slope Definition The “toe” of a slope is essentially the bottom, or baseline section, of the soil mass comprising the slope. It is also defined as the outermost margin of displaced material during a landslide. The toe of a slope is farthest away from the head scarp.

Contact Metamorphism Contact Metamorphism – Metamorphism is associated with the intrusion of an igneous mass. Metamorphic changes are caused principally by heat, but also by magma composition and deformation related to the intrusion. Pressures are relatively low (<3000 bars) while temperatures range from 200°C to 1000°C.

Rigidity Definition Rigidity – In geotechnical engineering and engineering geology, rigidity represents the ratio of the shear stress and the amount of angular rotation that it produces, within a rock sample.

Hydraulic Head Hydrualic Head: In the field of hydrogeology, hydrualic Head is a measure of the potential energy of a fluid at any given point in a hydraulic system. It explains the potential energy driving fluid flow by summing the elevation of the fluid and the pressure it exerts.