Published on : Jun 28, 2018
A recent research on understanding earthquake dynamics was conducted by the University of Illinois at Urbana-Champaign. The researchers gained a nanoscale knowledge that describes the relationship between friction, water, and mineral chemicals for earthquake dynamics. The engineers used microscopic friction measurement to establish that a rock can dissolve under certain conditions. As per their publication in a journal, Nature Communication, studies about minerals like calcite that are easily found in earth’s crust and the manner in which they interact at various pressures and in groundwater composition influences frictional forces along faults.
As per the co-author of the study and a professor of civil and environment engineering Rosa Espinosa Marzal ‘water is present everywhere’. Presence of water has been seen on the surface of minerals and in its pores especially in mineral grains in rock. Various studies have stated that the presence of water is related to fault movement and earthquakes, however its exact mechanism is difficult to track.
The main focus of the study is on calcite-rich rocks found in natural salty groundwater around the fault surface. As the physical and chemical properties of faulted rocks and its mechanism is complex, it is difficult to take down every single detail. Thus, to trail down the role of water in fault dynamics the researchers took a scaled-down simplified model to examine single asperities on each calcite crystal.
After the experiment they were able to demonstrate that certain brine-calcite interaction, while under applied stress, reduces the friction strength, and induces dissolution at every single asperity scale. By this research they were also able to suggest that one can possibly mitigate an earthquake risk by changing the brine composition on purpose in areas that contain calcite-rich rocks. Though this concept requires cautious investigation, but will be beneficial in areas prone to fracking as termed by Espinosa-Marzal.