Fault Zone
Fault zones are areas of rock that are subject to high levels of strain and shearing, resulting from the presence of fault lines. Fault zones are typically characterized by seismic activity, field slips, and/or displacement of rock material. Most fault zones are shown in seismic sections as a combination of two or more branch faults (or segments) that diverge from each other and often join at a single point. Fault zones are studied to better understand the tectonic processes that may have formed them.
Fault zones occur in what scientists refer to as a ‘tectonic setting’. This is a broad term for a number of forces, both natural and human-caused, that cause the formation of fault zones. These forces include underground seismic shocks, when subterranean rock is suddenly displaced horizontally by motion in the earth’s crust; adjustments of geologic plates (lithospheric plates) as they move independently through Earths mantle; glacial movements that deform landscape; and even human activities like energy exploration and construction.
Fault zones often act as pathways through which seismic energy travels, allowing energy to propagate at greater distances than on normal solid ground. Near major fault zones, seismometers can detect further seismic activity occurring away from the onset location of the primary tremor. This is referred to as an offset seismicity’.
The two most common types of fault zones found in nature are thrust faults, where the top of a fault plane moves up relative to the bottom, and strike-slip faults, where the top of a fault plane moves laterally relative to the bottom. Strike-slip faults are usually caused by the horizontal forces exerted by two lithospheric plates that move parallel to each other.
Fault zones provide information on past geologic events and can provide clues to location of buried materials like oil and gas deposits. Using seismic surveys and other geophysical methods, scientists can identify fault zones and then use them to infer the structure of the subsurface rocks. With this knowledge, potential oil and gas fields can be identified and mined.
Fault zones can also provide information on regional tectonic activities such as earthquakes, volcanic eruptions, subsidence, and mountain formation. By locating the fault lines, scientists can identify the tectonic plates boundaries and reconstruct the path of the plates. This helps to better understand the geological processes that have shaped the land and can provide insight into future geological processes that may occur in the future.
Fault zones provide an incredibly important resource for understanding the Earth’s geologic history as well as predicting its future. By providing more insight into the dynamics of the Earths crust and the distribution of materials therein, scientists can better understand natural hazards and have the ability to make better-informed decisions to protect the environment.
