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In addition, Klose estimates that human activity caused one-fourth of Britain's quakes, not just from mining. An Andrew Alden geology.about.com article headlined, "Earthquakes in a Nutshell" says:
"Earthquakes are natural ground motions caused as the Earth releases energy. The science of earthquakes is seismology (the study of shaking). Earthquake energy comes from the stresses of plate tectonics. As plates move, the rocks on their edges deform and take up strain until the weakest point, a fault, ruptures and releases the strain."
Five major types of human activity cause them:
(1) Damn construction
Since water is heavier than air, the crust beneath it is greatly stressed, easily setting off shocks that mostly are moderate. University of Alaska seismologist Larry Gedney explained:
"Since the (Hoover Dam) reached its peak of 475 feet in 1939, the level of seismicity has fluctuated in direct response to water level. None of the shocks have been particularly damaging - the largest was about magnitude 5 - but the area had no record of being seismically active."
Klose says dams cause about one-third of human-caused quakes. No wonder given their global proliferation, 845,000 according to Discover magazine, including 80,000 in America. Hoover Dam is the largest, storing 1.2 trillion cubic feet of water. China's Three Gorges Dam is the world's largest, holding back 1.4 trillion cubic feet. In 1967, a human-triggered 7.0 magnitude western India quake may have been caused by the Koyna Dam. If so, damns in seismically active areas may be more destructive than believed.
(2) Liquid injection into the ground
In 1951, the US Army constructed Basin F at the Rocky Mountain Arsenal to handle 243 million gallons of contaminated liquid chemical wastes in about a 93 acre area. In 1961, another way was chosen - by drilling a 12,000-foot deep well in the Rocky Mountains to inject napalm toxic waste into the earth's crust. From 1962 - 1966, 165 million gallons went in, likely triggering regional quakes and getting the Army to shut it down. According to seismologist Dave Wolney:
"If you are doing deep well injection, you are altering the stress on the underlying rocks and at some point, (it) will be relieved by generating an earthquake."
Klose also worries about carbon dioxide sequestration, a process of compressing CO2 from coal plants and injecting it into underground deposits. They, too, can generate quakes close to cities, as that's where facilities are located.
(3) Coal mining
Coal provides over half of America's electricity and an even larger percentage in China. Mines produce millions of tons annually, extract up to a dozen times as much water as coal, and cause huge regional mass changes. They, in turn, increase stress that can cause quakes as explained above. According to Klose, mining produces over half of recorded ones.
(4) Oil and gas drilling
A June 23, 2009 New York Times article headlined, "Deep in Bedrock, Clean Energy and Quake Fears," explaining that former oil man, Markus O. Haring, drilled a hole three miles deep in Basel, Switzerland prospecting for clean, renewable energy deep within the earth's bedrock. On December 8, 2006, an earthquake terrifyied residents who remembered the devastating one striking the city 650 years earlier.
Haring terminated his project, but a US start-up company, AltaRock Energy, will use the same technology to drill deep into quake-prone areas two hours' drive north of San Francisco for geothermal energy. The Energy Department backs it with more than $36 million, and several large venture capital firms are involved, despite the risk.
