Transgression: In geology, the term transgression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water advancing onto land. To illustrate, when transgression occurs over millions of years, geologists find a layer of sand, overlain by shale, and overlain again by limestone. The opposite of transgression is regression.
Moment Magnitude (M) Moment Magnitude (M): In the seismology branch of geology, moment magnitude is the magnitude of an earthquake that scientists estimate by using the Seismic Moment.
Volatile Organic Compounds (VOCs) 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…
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.
Darcy’s Law In the field of geology, Darcy’s Law is the universal and basic equation representing groundwater flow through a study area. Darcy’s Law Formula Q = KiA The following variables and coefficients apply to this formula: “K” = Hydraulic Conductivity; “Q” = Discharge Rate; “A” = Area of Cross-Section that Water Flows;
Contact Metamorphism Contact Metamorphism – Metamorphism is associated with the intrusion of an igneous mass. Metamorphic changes are caused principally by heat, but also by magma composition and deformation related to the intrusion. Pressures are relatively low (<3000 bars) while temperatures range from 200°C to 1000°C.
Liquefaction Liquefaction: Liquefaction is the process by which there is: (1) a sudden and significant decrease of shear resistance in a soil sample (cohesion-less); (2) a sudden (but temporary) increase of the pore-water pressure of a substance; and (3) a solid mass of soil that is transformed into a fluid state mass. In the event…
