Scientists have found how fluids, such as water, become sealed within the earth’s fault planes for a long period of time. This fluid pressure makes it easier for the earth’s plates to move alongside each other, eventually resulting in an earthquake.
Dr Dan Faulkner explains: “The difficulty with predicting earthquakes is that we know so little about how fault planes work. Over the years we have found that even small stresses acting on the earth’s plates can cause large earthquakes. For example the Loma Prieta earthquake in 1989 caused massive devastation, yet there was very little stress acting on the plate boundary to cause the quake in the first place.
“In theory, high stresses are needed to cause slip along a fault plane, but if something like pressurised water or gas gets inside the fault then it should act as a kind of cushion, making movement between plates easier and an earthquake more likely. Until now a problem with this theory was that as fluid pressures increased the rocks would crack and the fluids could escape through the cracks, reducing the ‘cushion’ effect. Our recent study, however, found that much smaller cracks surrounding the fault plane change the stresses acting on the rock, reducing the likelihood of significant cracks forming and allowing the fluid to escape.”
The team measured the density of ‘microcracks’ in the rock near the Chile fault line and applied varying amounts of stress to the rock to see how it responded. They found the ‘microcracks’ changed the elasticity of the rock, which meant stresses that might normally occur at almost right angles to the fault line rotated to a 45 degree angle instead.
Under normal stresses fluid would build up to such as extent that the rock would break and the fluid would escape, reducing the risk of an earthquake. When stress, however, occurs at a 45 degree angle the rock is less likely to break and the low fluid pressures inside can cause earthquakes.
Dr Faulkner added: “We now need to conduct further study into where these fluids and gases are coming from. Scientists are currently drilling of the San Andreas Fault in California, to help us understand more fully the mechanics of fault zones and how earthquakes occur.”
The San Andreas Fault Observatory at Depth (SAFOD) is a deep borehole observatory that will measure the physical conditions under which plate boundary earthquakes occur. Dr Faulkner is one of only two UK scientists who currently have access to rock drilled from the San Andreas Fault, which will be analysed in order to understand fault behaviour.
Dr Faulkner’s research is published in Nature Magazine.
Samantha Martin | alfa
New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences