Rock Stratigraphic Unit In the field of geology, a rock stratigraphic unit, or a lithostratigraphic unit, is a geologic formation that is identifiable by a specific lithology, as well as a consistent stratigraphic position. For example, the Monterey Formation is a rock stratigraphic unit, as it tends to consistently comprise the same gravel and sand…

Polychlorinated Biphenyl (PCBs) Polychlorinated Biphenyl (PCBs): Polychlorinated Biphenyl (PCBs) are highly toxic human-engineered chlorinated hydrocarbons that have been used around the world as enhancers to hydraulic oil and electrical insulators. PCBs were applied for maintaining low flammability rates, high boiling points, and stronger chemical stability. As of 1979, PCBs have been banned from use in…

Subsidence “Subsidence” is a geologic condition, in which a localized mass movement occurs, resulting in the downward settlement of the earth over time. When subsidence occurs, the actual ground surface elevation is lower. This occurrence of the ground surface sinking is typically caused by groundwater table and aquifer reductions, by which the soils become more…

Methane Alarm System Methane Alarm System: As per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a methane alarm system is part of an active methane mitigation plan. A methane alarm system is a group of interacting components and circuits that synchronize to monitor and annunciate the status of…

Hooke’s Law “Hooke’s Law” is a geological statement relating to the elastic deformation of rocks.  Hooke’s Law states the strain of an earth-material is linearly proportional to the applied stress.