The stress relief produced when earthquake strikes has always been one of the research hotspots in seismology, engineering, structural geology, mineral physics and some other disciplines. In order to have a better understanding of the earthquake mechanism, many countries including China, America and Japan have launched a series of deep drilling plans (such as Seismo-Fault Scientific Drilling Project of Wenchuan, China and Seismo-Fault Scientific Drilling Project of San Andreas, America), which aimed at taking out geologic materials in deep seismic area and systematically making physic chemical analysis to illustrate micro mechanism of the earth's crust brittle fracture and its influence on earthquake types.

Based on the previously developed new calibration method of Trigonal System Laue Diffraction Pattern (Journal of Applied Crystallography, http://scripts.iucr.org/cgi-bin/paper?S0021889812031287) , Doctor CHEN Kai, associate professor of Metal Material Strength Key Laboratory of Micro-Nano Scale Behavior Research Center of Xi’an Jiaotong University and scholar of the One Thousand People Plan of National Youth, and his partners have adopted Synchrotron Radiation X-ray Diffraction technology to analyze micro-scale residual stress of the quartz samples collected from San Andreas Fault. The result of the study shows that the distribution of residual stress of quartz samples from San Andreas Fault is extremely uneven, and the stress level is much higher than the average macroscopic stress produced in earthquake, which implies the different features of earthquake under macroscopic and microscopic scale.

Recently, the study has been published at the top scientific journal, Geology, and received high praise from reviewer, who thinks that this method is of significant importance for stress and strain characterization in microscopic scale and for its use in material and earth sciences.

This project is supported and subsidized by China's One Thousand Talents Plan, Department of Energy of the United States and National Science Foundation of the United States.