Triggered Creep In the field of geology, the term “Triggered Creep” refers to a type of creeping landslide, usually along a fault line, that is triggered by a source of seismic activity.

Hardpan (Caliche) “Hardpan” is a highly dense and solid layer of soil near the ground surface, which is usually comprised of clay or silty-clay soils. Hardpan forms by cementation over time, during the process of precipitation of insoluble substances such as calcium carbonates, silica, iron oxides, and other organic matter. “Hardpan” is a term mostly…

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…

Unconfined Aquifer Unconfined Aquifer: In the hydrogeology branch of geology, an unconfined aquifer is an aquifer that has a water table. In fact, an unconfined aquifer can only be the uppermost hydrogeologic unit and is particularly one that has no hydraulic head (or pressure) that is equal to atmospheric pressure. To illustrate, depth to groundwater…

Time Stratigraphic Unit Definition A Time Stratigraphic Unit, or a Chronostratigraphic Unit, is a rock unit that is characterized by geological formations, during a specific period of time. This serves as a reference for all rocks formed during the same time period.

Recurrence Interval Meaning In the field of geology, the term “Recurrence Interval” refers to the average time interval that occurs between two recorded events of seismic activity, of equal magnitude, along the same fault.