Moment Magnitude (M)

“Dry Density” (ρd) is a value that represents the density of soil when it is completely dry. To illustrate, it equates to (“bulk density” / 1) + “water content.” This is a common geotechnical engineering laboratory procedure. Dry Density Formula Dry Density = [(Bulk Density ÷ 1) + (Water Content)]

Volatile Organic Compounds (VOCs): Volatile Organic Compounds are toxic organic chemicals with higher tendencies to change from liquid to vapor phase under typical earth pressures and temperatures, and usually have little-to-no water solubility characteristics. VOCs are commonly found within hydrocarbon-based fuel additives, industrial solvents, refrigerants, hydraulic fluids, degreasers, and more. These compounds are generally known…

“Dilatancy” is the increase in the bulk volume of a soil substance during deformation. Dilatancy is caused by the change from a close-pack structure to an open-pack structure.

“Adsorption” in geology, refers to the attraction and adhesion of the ions or molecules of a solution, onto the surface of a solid.

“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.

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 lighter end of the…