Professor Pascal Audet, Department of Earth Sciences, along with a team of researchers led by Professor Colin Amos of Western Washington University, has published an article in the scientific journal Nature that shows a direct link between human-induced groundwater depletion and the uplift of California's Sierra Nevada and Coast Ranges, which may increase the number of small earthquakes on the adjacent San Andreas Fault
Audet's role in this research was to model the upward motion of the Earth's crust caused by the removal of groundwater in order to match the pattern of uplift measured by Global Positioning System (GPS) data. The model was then used to calculate how the land motion alters the stress conditions on the San Andreas Fault.
The article shows that, in addition to affecting the Earth's outer fluid layers, including the atmosphere and oceans, human activity also lead to deformation of the Earth's crust. Such unnaturally caused deformation will likely become increasingly prevalent as climate scenarios forecast higher agricultural, urban and environmental groundwater use.
Any large-scale process that redistributes mass over the surface of the Earth, either human-induced, such as resource extraction, or natural, has the potential to cause ground deformation.
"In Canada, the strong landmass of the Canadian Shield may prevent large land motion and shield us, in essence, from associated effects such as earthquakes," states Professor Audet. "However, in light of this research, increased monitoring and modelling of land motion in areas of large-scale industrial activity may be called for."
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