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The Times published the following article by me last week. I
have inserted updates to clarify one issue.
On 1 June this year a Mr Andrew Noakes was having lunch in Shropshire when "I thought I
heard something. The sound only went on for a few seconds and then
it stopped. There was no shaking cutlery or furniture." It was a
natural earthquake, bigger than the ones caused by fracking in
Lancashire last year. Worldwide there are a million a year of a
similar size. Very few are even noticed. A magnitude 2.3 tremor is
to a dangerous earthquake as a tiny stream is to the Amazon: the
same sort of thing but much less likely to drown you.
By contrast, an earthquake that was 180 million times more
energetic killed 80,000 people in 2008 in Sichuan. We now know it
was almost certainly man-made, or at least man-triggered. The
Zipingpu reservoir, designed to generate hydro-electric power, had
been filled with water shortly before the fault beneath it
A report by Fan Xiao, chief engineer of the Regional
Geological Survey Team of the Sichuan Geology and Mineral Bureau,
analysed 60 studies of the event and concluded that "the mounting body of
evidence and analysis indicates that the magnitude 8 earthquake was
triggered by the mass loading and increased pore pressure caused by
the Zipingpu reservoir".
Admittedly the study was translated and published by Probe
International, a Canadian pressure group that campaigns against
large dams and is funded partly by the nuclear industry, but others
have reached the same conclusion. Professor Christian Klose of
Think Geohazards in New York has concluded that the 300m tonnes of water in
the Zipingpu reservoir effectively "advanced the clock" on a fault
that would not have failed for another 60 years.
That dams cause earthquakes is not a new or far-fetched idea. Dr
Klose has catalogued 92 man-made earthquakes, about half of which
were caused by dams. One at Koyna in India is still occasionally
causing the ground to shake decades after being filled. But think
of the implications of this news. It would make the Sichuan
earthquake the second largest man-made death toll in a single
event, after Hiroshima, but bigger than Nagasaki and Dresden.
To put it unfashionably, the second biggest man-made disaster on
record was caused by the search for renewable energy. Geothermal
energy, too, can cause earthquakes. Two years ago the city of Basel
called a halt to a project intended to extract heat from the rocks
deep beneath the city after an earthquake was caused by the
drilling. Basel was destroyed by an earthquake in 1356.
[Update: I am told that the company responsible
for the Basel event began an intensive programme of hydraulic
fracturing at depths up to 5km in contradiction to expert advice
and on an active fault boundary. Basel is actually the site of
Central Europe's largest ever earthquake in 1356 measuring 7.1 on
Richter. The lesson is NOT that geothermal energy -- or dams or gas
-- are inherently dangerous but that any of these activities in a
seismically sensitive zone near a build-up area are unwise though
quite safe elsewhere. Britain is a very very low risk place for big
earthquakes. It's the location, not the technology that
Compared with dams and geothermal projects, the seismic risks of
fracking, a procedure that has been used for 60 years to open the
pores in rocks to release oil or gas, are not only very small, but
extremely well tested. More than 100,000 frackings were carried out
in the United States last year and none caused a tremor larger than
the Blackpool one-which was in any case barely enough to cause a
ripple on your coffee.
If it's earthquakes that worry you, campaign against dams, not