The most accurate statement comparing the environmental impact of underground mining and hydraulic fracturing from the provided options is:
Both can cause earthquakes.
This is because hydraulic fracturing (fracking) has been associated with induced seismicity due to the injection of fluids into the earth, and while underground mining can create instability in the ground that might also lead to localized seismic events, it is not a primary concern in the same way fracking is. The other options do not accurately apply to both methods.