Research on the features of the Benioff strain ratio in Xinjiang region before earthquakes above MS6.0

Before a strong earthquake occurs, the phenomenon of accelerated release of strain energy is common in the area near the epicenter, indicating that the seismogenic area is approaching or entering a critical state. Taking the Benioff strain as the response quantity, the Benioff strain ratio at different periods is calculated, which can be used as a parameter to characterize the speed of strain energy release, and its abnormal evolution reflects the high-stress state of the intermediate substance during seismic nucleation. Using the catalog provided by China Earthquake Networks Center, the Benioff strain ratio of 90 days per month was calculated one year before the M6 earthquakes in Xinjiang since 2000 on the basis of analyzing the completeness thresholds magnitude. The results show that 14 of the 18 groups’ earthquakes were located in the high-value anomalies region within one year,passing the prediction effect test, which indicates that the high-value anomaly of the Benioff strain ratio has mid-short term prediction significance for M6 earthquakes in Xinjiang region. Taking the Aketao M6.7 earthquake and Hutubi M6.2 earthquake in 2016 as examples, the strain ratio in the seismogenic zone showed the characteristics of "gradually increasing - rapidly decreasing - stable fluctuation" within one year before the earthquake, which may be related to the instability nucleation process of the fault.