Credit: University of Southampton
In the United States it has become so popular for anti-science groups to blame hydraulic fracturing - fracking - for earthquakes that it might seem like little actual research is being done without an agenda.
There is elsewhere. A team of scientists have done chemical analyses of the geothermal fluids and mineral veins from the Southern Alps of New Zealand, where the Pacific and Australian Plates collide along the Alpine Fault, and found that they are derived from rainwater and channeled up the Fault - enough to promote earthquake rupture on this major plate boundary fault.
Like the San Andreas Fault, the Alpine is a major strike-slip fault that fails in very large (Magnitude 8+) earthquakes about every 300 years. It last ruptured in 299 years ago sobecause it is a rare example of a major fault that is late in the strain-build up before rupture, it is under intense scientific scrutiny.
Lead researcher Dr. Catriona Menzies, from Ocean and Earth Science at the University of Southampton, said,
"We show that the Alpine Fault acts as a barrier to lateral fluid flow from the high mountains of the Southern Alps towards the Tasman Sea in the west. However, the presence of mantle-derived fluids indicates that the fault also acts as a channel for fluids, from more than 35 km depth, to ascend to the surface.
"As well as mantle derived fluids, our calculations indicate that 0.02-0.05 per cent of surface rainfall reaches around six kilometres depth but this is enough to overwhelm contributions from the mantle and fluids generated during mountain-building by metamorphic reactions in hot rocks. This rainwater is then focused onto the fault, forced by the hydraulic head of the high mountains above and the sub-vertical fluid flow barrier of the Alpine Fault."
Citation: Dr Catriona Menzie et al., ‘The fluid budget of a continental plate boundary fault: Quantification from the Alpine Fault, New Zealand’, Earth and Planetary Science Letters, DOI: doi:10.1016/j.epsl.2016.03.046
