Establishing a link between fracking and earthquakes was
''difficult'', but circumstantial evidence pointed to there
being one, Dr Andreas Lindstrom told an audience on Saturday at
the Otago Foreign Policy School.
''How big an issue it is [seismic danger] I can't tell you,''
Dr Lindstrom, of the Stockholm International Water Institute,
in Sweden, spoke about pressures on water use from population
growth, agriculture, energy production, and the increasing
need for regional co-operation over water usage.
Hydraulic fracturing, or fracking, had enabled a
''revolution'' in shale gas production in the United States.
This had major geopolitical implications as energy production
moved to different parts of the world.
Fracking is an energy extraction process using up to 99.5%
water mixed with chemicals injected into rocks in order to
It did not use as much water as some other industrial
processes, but used fracking water could not be reused for
other purposes, except further fracking, he said.
Exactly how much water is consumed by fracking is unknown
because there was no standardised way of measuring water use.
Evidence of adverse health effects, including cancer, caused
by groundwater pollution from fracking was also
''circumstantial'', and companies were able to deny links.
Shale gas companies were strongly protected in law in the US,
prohibiting revealing the composition of chemicals used in
the fracking process.