Trench Dam Trench Dam: Per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a trench dam is part of a methane mitigation system. A trench dam is essentially a subsurface barrier that exists within a furrow or ditch, that is adjacent to the foundation of a building in a…

Fault Scarp Fault Scarp: In the field of geology, a dip-slip fault scarp is a steep slope that is formed directly by fault movement. It occurs along the line of a normal fault, reverse fault, or transform fault. A fault scarp represents the planer surface of the fault before erosion and weathering modify it.

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.

Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.

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.

Ultramafic Definition In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.