Polychlorinated Biphenyl (PCBs) Polychlorinated Biphenyl (PCBs): Polychlorinated Biphenyl (PCBs) are highly toxic human-engineered chlorinated hydrocarbons that have been used around the world as enhancers to hydraulic oil and electrical insulators. PCBs were applied for maintaining low flammability rates, high boiling points, and stronger chemical stability. As of 1979, PCBs have been banned from use in…

Asthenosphere Asthenosphere: The asthenosphere underlies the lithosphere. The Asthenosphere comprises the upper mantle, where isostatic adjustments are made, and where magma is generated. It is also in this part of the earth, where seismic waves strongly attenuate.

Volcanology Volcanology: Volcanology is a branch of geology that focuses on the study of volcanos. In volcanology, geologists conduct field and laboratory investigations to learn about continental, coastal, and submarine volcanic activities. In fact, volcanology ties into many other branches of geology. For instance, a volcanologist may study the geochemistry of igneous rocks, such as…

Transgression 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…

Hydro-Compaction Definition (Hydrocompaction) The term “Hydro-Compaction” or “Hydrocompaction” in engineering geology refers to the process whereby soils collapse upon saturation. Hydrocompaction can also be called “Hydro-Consolidation.”

Soil Creep Definition Soil Creep is a type of landslide that entails the slow and gradual movement of a soil mass (or even some loose rock) materials.