Alquist-Priolo Earthquake Fault Zoning Act Alquist-Priolo Earthquake Fault Zoning Act: The Alquist-Priolo Earthquake Fault Zoning Act is a law that assists geologists to define “active faults” versus “potentially active faults.” The process entails using the same aging criteria as the United States Geological Survey (USGS) and the California Geological Survey (CGS). In fact, California policy requires…

“Toe” of a Slope Definition The “toe” of a slope is essentially the bottom, or baseline section, of the soil mass comprising the slope. It is also defined as the outermost margin of displaced material during a landslide. The toe of a slope is farthest away from the head scarp.

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…

Connate Water Definition Connate Water: In geology, connate water is groundwater that has been trapped within the pore space of a sedimentary rock since its original deposition. Connate water is also referred to as “fossil water” due to a long history of non-exposure.

Petroleum Extraction Well (Oil Well) Petroleum Extraction Well (Oil Well): A petroleum extraction well, or an oil well, is a deep borehole or shaft sunk into the Earth for the exploration of oil or gas. Additionally, injection wells are often drilled to inject fluids or gas for stimulating oil recovery, re-pressurizing or pressure maintenance 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.”