Water Table: In the hydrogeology branch of geology, the water table represents the surface of an unconfined groundwater aquifer, where the hydraulic pressure is equal to atmospheric pressure. Additionally, a water table is present in a perched groundwater zone. Although, there is no water table in a confined aquifer.
Epicenter Epicenter: In the seismology branch of geology, an epicenter of an earthquake is the point on Earth’s surface that is directly above the focus (or hypocenter). It is the ground surface location overlying where an earthquake rupture originates within a dip-slip fault or strike-slip fault. Shortly after an earthquake, United States Geological Survey (USGS)…
Geologic Time Scale The Geologic Time Scale is an international system used by geologists to classify and identify major geologic events and formations. The geologic timescale essentially categories the earth’s entire geologic (and biologic) history, within a series of defined eons, eras, periods, epochs, and ages. Updates & Maintenance The geologic time scale is continuously…
Leaking Underground Storage Tank (UST) Leaking Underground Storage Tank (LUST): A leaking underground storage tank (LUST) is a known case of hazardous liquid materials released into the environment, from within an underground storage tank (UST) source. The term “LUST” commonly applies to gasoline station soil contamination cases overseen by environmental regulatory agencies. Also See: Underground…
Hydro-Compaction Definition (Hydrocompaction) The term “Hydro-Compaction” or “Hydrocompaction” in engineering geology refers to the process whereby soils collapse upon saturation. Hydrocompaction can also be called “Hydro-Consolidation.”
“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.
De-Watering System in Methane Mitigation De-Watering: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a de-watering system is a permanent water removal system in a methane mitigation system. In the mitigation process, a de-watering system consists of perforated horizontal pipes, gravel pockets, sump areas with pumps,…
