The subsoil is in constant motion, which is why minor and major quakes shake the earth every day. However, not all of these vibrations are of natural origin – some are triggered by human activity. In such cases, science speaks of “induced earthquakes” or “induced seismicity.” This is often caused by major technological activity in the subsoil. With few exceptions, these earthquakes are very small and hardly noticeable on the surface.
In Switzerland, man-made quakes are mainly related to geothermal energy projects. In 2006, an earthquake with a magnitude of 3.4 was triggered in Basel by water being injected at high pressure into the ground, and an earthquake with a magnitude of 3.5 was also triggered near St. Gallen in 2013.
But earthquakes are also triggered when the subsoil is breached for other reasons, such as the injection of CO2 or wastewater, for the conventional and unconventional extraction of crude oil and natural gas through fracking, or in mining and tunneling. Furthermore, man-made alterations to the earth’s surface can also trigger earthquakes. An example of this is the filling of reservoirs with water for the first time.