Oil and gas extraction can cause small, slow-moving, and longer earthquakes that scientists have recorded for the first time in Canada’s Franking oil and gas fields.
A team from the Geological Survey of Canada has recorded a new type of earthquake caused by ruptures near an active gas well. The data from these earthquakes help scientists explain how almost imperceptible vibrations from oil and gas extraction processes can cause larger earthquakes.
The study shows that about 10% of the 350 earthquakes recorded over the past five months at a distance of several kilometers from an active gas well in British Columbia, Canada, are slower than normal earthquakes due to crustal fractures. In other words, these earthquakes last a few seconds longer.
“We assumed that quake-induced earthquakes behave like other earthquakes and have about the same velocity of expansion – two to three kilometers per second,” said Rebecca Harrington, a seismologist at the University of Rohr Bochum in Germany.
Hydraulic fracturing is a process used in the oil and gas industry to pump pressurized liquids into drilled wells. This process causes small fractures in the subsurface rocks. It also pumps large amounts of sewage into basement areas, which can put significant pressure on fault lines.
Using network data from seismic stations around an active well, the researchers recorded combined-frequency earthquakes, a feature characteristic of normal earthquakes, that lasted up to about 2 seconds. In their paper, Harrington et al. Expressed concern about larger and longer earthquakes. The largest earthquake due to a crustal fracture in 2018 shook China, the magnitude of which was estimated at 5.7 Richter. Although these man-made earthquakes are very rare, we see that they can cause serious damage.
In this regard, experts argue that increasing our understanding of this type of earthquake can help better manage it and reduce the risks. But the fundamental question is: Given the path that our planet is taking – in terms of global warming – is it not time to stop using fossil fuels?