US government geologists have reported that the number of earthquakes in the central United States rose "spectacularly" near where oil and gas drillers fracked.
The average number of earthquakes of magnitude 3 or greater in the US mid-continent - an area that includes Arkansas, Colorado, Oklahoma, New Mexico and Texas - increased to six times the 20th century average last year, scientists at the US Geological Survey said in an abstract of their research.
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The Office for National Statistics said gross domestic product grew by just 0.1%.
William's comments came during a surprise appearance at an event scheduled for just his brother.
Matt Campbell, who collapsed just a few miles from the finish line, had hoped to raise £2,500.