Analysts raise doubts about fracking-induced quakes
The rapid ascension of hydraulic fracturing as the drilling method of choice to free up oil and gas from shale and tight rock formations across North America has been followed almost as swiftly by public concerns about the environmental impacts of the practice. Critics contend the drilling technique poses a risk to groundwater. Others have tried to link the earth-shattering extraction method to minor earthquakes. Analysts and industry participants say the connection is iffy. Below is a snapshot of several petroleum-related temblors, including two from Alberta.
Source: United States Geological Survey