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 methane zone or methane buffer zone. And the purpose of a trench dam is to prevent the migration of methane soil gas through any permeations of a building foundation.
Regression Regression: In geology, regression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water withdrawing from the land. To illustrate, when regression occurs over millions of years, geologists find a layer of limestone, overlain by shale, and overlain again by limestone. The opposite of regression is…
Index Fossil Definition An Index fossil, in the field of paleontology, refers to a fossil that identifies and dates the stratigraphic unit that it is observed to exist in. Index fossils can combine a wide geographic range. And they can really narrow down the classifications of most stratigraphic units.
Seismology Seismology: (seis·mol·o·gy) a branch of geology and geophysics that relates to earthquakes, including but not limited to their causes, effects, hazards, and mitigation techniques. Seismologists at the United States Geological Survey (USGS) use cutting-edge technology to measure seismic wave properties and geological hazards that trigger them or are triggered by them. In turn, seismology…
Liquid Limit (LL) “Liquid Limit (LL)” in the field of geological engineering, refers to the upper limit of the “plastic state.” This is a separation of the plastic phase and viscous liquid phase when measuring soil consistency. Mathematically, it is the water content (basing on the percent of dry weight), at which two sections of…
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…
Licensed Professional Geologist A “Licensed Professional Geologist” or a “Certified Professional Geologist” is a person who is certified by a State and/or Federal agency (such as the California Department of Consumer Affairs, Board for Professional Engineers, Geologists & Land Surveyors), and has proven be educated, formally trained and professionally competent per government standards, to practice…
