Reverse Fault Reverse Fault: In the field of geology, a reverse fault is a dip-slip fault in which the hanging wall moves upwards, relative to the footwall. The average dipping angle of a reverse fault ranges from 45 to 90 degrees. However, if less than 45 degrees, it becomes a “thrust fault.” Reverse faults are…

Rigidity Definition Rigidity – In geotechnical engineering and engineering geology, rigidity represents the ratio of the shear stress and the amount of angular rotation that it produces, within a rock sample.

Passive Methane Mitigation Passive Methane Mitigation: Passive systems refer to the non-mechanical and non-electric components of the methane mitigation process. These components remove the vapor intrusion risks of methane soil gas migration into buildings atop Los Angeles Methane Zones and Methane Buffer Zones. In fact, methane testing results typically indicate the necessity for a passive…

Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.

Subsidence “Subsidence” is a geologic condition, in which a localized mass movement occurs, resulting in the downward settlement of the earth over time. When subsidence occurs, the actual ground surface elevation is lower. This occurrence of the ground surface sinking is typically caused by groundwater table and aquifer reductions, by which the soils become more…

Ultramafic Definition In the study of geology, the term “ultramafic” refers to an igneous rock that comprises up to 90% mafic minerals, or more.