In seismology, induced seismicity refers to earthquakes that are caused by human activity. It occurs when this activity alters the stresses and strains in the Earth's crust. Most induced seismicity is of an extremely low magnitude, and in many cases, human activity is merely the trigger for an earthquake that would have occurred naturally in any case.
There are a number of ways in which induced seismicity has been seen to occur:
The mass of water in a reservoir alters the pressure in the rock below, which can trigger earthquakes. Reservoir-induced seismic events can be relatively large compared to other forms of induced seismicity.
Inducedseismicity describes earthquakes that in one way or another are related to human activity.
Earthquakes are mainly induced in three antropogenic settings, (1) in mines, (2) in connection with large water reservoirs and (3) in oil or gas fields where hydrocarbons are extracted.
Reservoirinducedseismicity in connection with large hydropower dams has been well known for at least 60 years, and inducedseismicity in connection with ore mining has a history of at least 100 years.
Reservoir-induced seismicity in connection with large hydropower dams has been well known for at least 60 years, and inducedseismicity in connection with ore mining has a history of at least 100 years.
The problems relating to inducedseismicity have been known from oil and gas fields since the 1920s, and was 30 years later thoroughly studied at an oil field near Wilmington, California, where the oil production triggered a series of damaging earthquakes.
Inducedseismicity can involve large and damaging earthquakes as in Uzbekistan or in California, however, more frequently we observe micro seismicity or `cracking' in an exploited reservoir as shown for an oil field in the figure.
Feeds |
Contact