Can fracking cause bigger, more frequent earthquakes?

Injecting fluids into the Earth, whether to recover natural gas or to obtain thermal energy from the planet, can cause earthquakes. New reports that look at American fracking, deep waste-water injection, and geothermal activities suggest there are big risks and thus a need to develop strong regulatory framework to deal with them.

The most striking indication of human-induced earthquakes is provided by the graph below, which shows the cumulative number of earthquakes in the central and eastern US that were greater than or equal to magnitude 3.0 on the Richter scale. The clear increase from 2005 coincides with the rapid increase of shale gas wells and associated increased, deep waste-water injection. Between 2005 and 2012, the shale gas industry in the US grew by 45 percent each year.

William L Ellsworth/Science

Three reports have been published this month in Science that add to our limited but growing data on the causal link between fluid injections and earthquakes.