Metamorphic Rock Definition In the field of geology, the term “Metamorphic Rock” refers to a rock classification that is the result of the alteration of prior existing sedimentary rocks or igneous rocks. The alteration process is “metamorphosis, and can take place by various methods and environments. The metamorphosis process produces specific metamorphic rocks, on the…

Gap-Graded The term “Gap-Graded” is used by geologists, engineers, and soil scientists in the geotechnical engineering field to describe the gradation of a soil sample, specifically when some particle sizes are missing. Aside from being “gap graded,” a soil sample can be described as “well-graded” (also referred to as poorly sorted), or “poorly graded” (or…

Effective Stress (σ’) “Effective Stress” (σ’) is a geotechnical engineering term. Effective Stress is a function of “total stress,” and is due to the solid particles of soil. Effective stress represents an excess of stress above pore-water pressure (or neutral stress). Effective Stress Formula Effective Stress = Total Stress – Pore-Water Pressure.

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.

Mineraloid Definition The term “mineraloid” refers to a natural earth substance that appears to be similar to a genuine mineral, although lacks any form of internal structure and crystal form. Nonetheless, a mineraloid does comprise true minerals within it. For instance, Fire Opal and Blue Opal are not minerals because they are amorphous (do not…

Unobstructed Opening Definition in Methane Mitigation Unobstructed Opening: Per the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, an unobstructed opening is a permanent clearance or gap in the walls, floors, or ceiling of a structure, to allow for direct fresh airflow. In methane mitigation plan applications, this does not…