Impervious Membrane: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, an impervious membrane is a continuous methane gas barrier. It is a crucial part of the methane mitigation process and underlies a building to impede the vapor intrusion of methane soil gas. An impervious membrane must comprise materials approved by the LADBS.
Diagenesis Diagenesis: In geology, diagenesis refers to the physical and chemical changes of a sedimentary formation when compaction and lithification occur over time.
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)…
Volcanic Rock (Igneous) Definition A “Volcanic Rock” is an igneous rock that is finely crystalline and glassy (or aphanitic). To illustrate, volcanic rocks result from volcanic action at the earth’s surface. Typically, this also includes igneous intrusions that are “near-surface,” which may otherwise be considered plutonic. This action results in a final rock that is…
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.
Extrusive Rocks Extrusive Rocks: In the volcanology branch of geology extrusive rocks are igneous rocks that have been erupted onto the Earth’s surface, before forming and crystallizing. On the other hand, intrusive rocks form and crystallize under the Earth’s ground surface. Extrusive rocks are typically microcrystalline and aphanitic, because of the faster rate of cooling…
Permeability “Permeability” in engineering geology and geotechnical engineering refers to the property of a soil sample (or porous rock) which relates to transmitting a fluid within. Permeability measures the relative case of flow under unequal pressure. Permeability is calculated using Darcy’s Law.
