Zoning Mineralogy Definition Zoning is a variation of crystal composition that is a characteristic of feldspars. To illustrate, the center of a feldspar mineral is formed by a high-temperature phase, whereas the exterior is formed by a low-temperature phase.

Passive Methane Mitigation Passive Methane Mitigation: Passive systems refer to the non-mechanical and non-electric components of the methane mitigation process. These components remove the vapor intrusion risks of methane soil gas migration into buildings atop Los Angeles Methane Zones and Methane Buffer Zones. In fact, methane testing results typically indicate the necessity for a passive…

Total Petroleum Hydrocarbons (TPH) Total Petroleum Hydrocarbons (TPH): The term “Total Petroleum Hydrocarbons” represents the complete carbon chain of hydrocarbon compounds that originate from petroleum. In general there are three ranges of TPH: Gasoline Range Total Petroleum Hydrocarbons (TPH-g); Diesel Range Total Petroleum Hydrocarbons (TPH-d); and Oil Range Total Petroleum Hydrocarbons (TPH-o). Gasoline range TPH represents the…

Biogenic Gas Biogenic Gas: In geology, biogenic gas refers to natural gas that is the byproduct of the microbial decomposition of biological and organic matter. For instance, methane soil gas on Earth is typically a biogenic gas resulting from the decomposition of organic soil zones, landfills, marshes, and swamplands. Alternatively, natural gas can be petrogenic…

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…

Normal Fault Normal Fault: In the field of geology, a normal fault is a type of dip-slip fault where the hanging wall moves downwards from the footwall. The average dipping angle of a normal fault ranges from 45 to 90 degrees. Normal faults are the opposite of reverse faults. Detachment Fault Detachment Fault: A detachment…