Induced seismicity: the potential hazard from shale gas development and CO geologic storage.

We present an overview of the current status of unconventional energy development, particularly of shale gas, and underground CO storage as a measure to mitigate greenhouse gas increase in the atmosphere. We review their potential to induce seismicity, which has caused debates among related energy enterprises, engineers, researchers, and environmental and public communities regarding their potential hazards. Studies show that fracking can be a problem in that it consumes abundant water, but the seismicity induced by fracking has not yet been observed to induce many felt earthquakes. However, massive wastewater injection, a part of the unconventional energy development process has caused M5.0+ earthquakes in the past as well as several recent and ongoing cases of induced seismicity. Large-scale CO injection as a part of carbon sequestration efforts in the near future has a high risk of inducing large earthquakes. Therefore, injection operations related to both unconventional energy development and carbon sequestration should be optimized and managed to mitigate the likelihood of an induced seismic event. [ABSTRACT FROM AUTHOR]