Understanding of geological processes from nanoscale minerals

The nanoparticles, particles with diameters of 1 to 100 nm, are common in diverse geological environments because the low temperature on the surface of the earth is a suitable environment for the formation of nanoparticles through geochemical, biological, and mechanical processes. The physical and chemical properties of nanoparticles are different from bulk materials because of their large surface area resulting from the small particle size. Understanding the unique properties of nanoscale minerals is essential to comprehending the geological processes in the earth’s surface and interior. As one such case, I would like to present the role of nanoscale minerals in the slip behavior of the fault. Mechanical deformation processes, such as pulverization, occur extensively in slip zones and can affect the shear strength of active and mature faults because the minerals in the fault gouge are exposed to repeated mechanical deformation due to reoccurring slip movement. For instance, pulverization of minerals such as illite and dolomite lowers the thermal decomposition temperature of dolomite or silicate compared to before, which results in the fault weakening by thermal pressurization through the releases of H₂O or CO₂. The mechanochemical effect on slip strength is not fully understood and necessary extensive investigations from an earthquake propagation perspective.