In May, Cuadrilla Resources had to stop drilling in Lancanshire, Britain because two tiny tremors of 2.3 and 1.5 magnitude were recorded in the region. Exploration was halted over concerns that the seismic activity had been caused by deep drilling and hydraulic fracturing which blasts huge volumes of water through rock at high pressure to extract the gas. The company commissioned a report by a team of independent seismic experts who concluded that the company's fracking probably did cause the seismic shocks.
The Oklahoma Geological Survey has found that hydraulic fracturing may have triggered a series of 50 seismic events in Oklahoma that followed a 2.8 magnitude quake. Among other recommendations, the Shale Gas Subcommittee of the Secretary of Energy's Advisory Board requested more research on “Understanding induced seismicity triggered by hydraulic fracturing and injection well disposal.”