Having been taught seismology by Prof Peter Styles, who developed a traffic-light monitoring system in the 1980s that dramatically reduced the impact of coal mining under Swansea for local residents, I believe Jacob Rees-Mogg has a risible scientific understanding about shale gas extraction (Tory MPs angrily challenge Rees-Mogg’s fracking revival plan, 22 September). Vibrations from quarries and building sites tend not to be widespread, compared to shaking generated a few kilometres beneath an area.
The current 0·5 magnitude limit was set so tremors should not rise above 2·5, “because of the increased risk of larger magnitude events”, according to a recent British Geological Survey report. Proposing a higher limit would be reckless, as any anthropogenic tremors above 3 could prove to be destructive – not least to the Tory vote, if people’s houses start crumbling.
Above the Groningen gas field in the Netherlands, many houses were destroyed by frequent shaking triggered by over-hasty extraction rates.
David Nowell
Fellow of the Geological Society
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