More evidence for fracking causing earthquakes:
Earthquake by natural Fracking
Sensitive seismometers characterize shock that are generated from moving fluids in the subsurface
Soil column after the Yushu earthquake of 14 April 2010, which was not caused by Fracking
Taipei (Taiwan) - Moving fluids under high pressure through a deep rock, earthquakes can be triggered. This process could now examine an international team of geophysicists in an earthquake in Taiwan in more detail. This was made possible with about two kilometers deep hole that was made after the devastating Chi-Chi earthquake-1999 directly into the region in the geological fault zone. The results of this study, the researchers published in the journal "Science" could be especially important for energy companies in the shale-bound natural gas by means of compressed fluids at depth - want to promote - the so-called Fracking. "The movement of high-pressure fluids in the subsurface - either through natural processes or injected with industrial activities - has the potential to trigger major earthquakes," write Kuo-Fong Ma of the National Central University in Taiwan and their colleagues from Japan and the United States. However, this effect could be previously never studied directly in a fracture zone. Thanks to a whole network of Seimometern that can register themselves smallest earthquakes, the research team have now been able to identify a clear link between the moving fluids in the subsurface and vibrations in the rock.
Since the rock layers led around the hole itself sufficient quantities of water, the researchers needed to inject liquids. The prevailing water pressure was sufficient to produce in the fracture zone further small rock fractures. This resulted in weak shocks, which could be detected by the sensors in the borehole and the surface. Approximately 100 of these mini-quake could record the researcher during a month. Since non-classical mechanisms of earthquakes, but the water movements were responsible for these earthquakes, they gave a new name: I-type events.
Such quakes can cause damage as a result of a natural hydraulic Frackings on the surface hardly. However, fluids are injected under high pressure into the ground, are more rock quarries and thus greater earthquake in the realm of possibility. For those looking for natural gas and oil in geologically unstable areas, such as in these experiments Fracking hence carries a non-negligible risk of earthquakes.
© Wissenschaft aktuell
"Isotropic Events Observed with a Borehole array in the Chelungpu fault zone, Taiwan", K.-F. Ma et al, Science, Doi. 10.1126/science.1222119
Translated by Google. Original article => Erdbeben durch natürliches Fracking
Also => Forcing fluids through a fault
The movement of high-pressure fluids -- either from natural processes or from industrial activities that inject fluids underground -- has the potential to trigger large earthquakes by opening up cavities and cracks deep underground. However, until now, researchers had never directly observed this fluid-driven process in a fault zone. By studying the fault along which the magnitude 7.6 Chi-Chi earthquake occurred in Taiwan back in 1999, Kuo-Fong Ma and colleagues identified several small earthquake-like events, which they called I-type events. This Chelungpu fault zone currently exhibits low tectonic stress and the I-type events are so small that they register negative magnitude values. But, after modeling these I-type events, Ma and the other researchers suggest that they are associated with natural hydraulic fracturing, or the break-up of rocks by high-pressure fluids. The presence and location of these events can indicate when and where such fracturing is occurring, they say. These I-type events may indicate the formation of veins or other fluid features that are often observed in rocks surrounding active fault zones, and according to the researchers they might also be similar to the events produced by industrial fracking.