Quantitative analysis of influence factors of Xidaicun cross fault short levelling in August 2023
In August 2023,the short leveling cross fault measurement of section 3-2 in Xidaicun showed an accelerated rise and abnormal changes exceeding the threshold.The variation amplitude of the data in a single period was 2.12 mm,which was much larger than the 0.2 mm variation in June 2023.After investigating the observation system,environmental interference,and earthquake anomalies,it was found that:①The instrument operates normally,excluding the influence of the observation system.②Human influence:There are no new large-scale industrial and agricultural production or engineering construction impacts near the site,excluding the interference from human production activities.③ Environmental interference:With the increase of rainfall in the study area,surface runoff is formed in the Shili River(which is almost parallel to the section 3-2 and has been dry all year round).The depth of accumulated water near the survey line is about 1 m.Using the irregular load simulation,the load change caused by accumulated water is calculated,and an estimated load value of about 0.73 mm is obtained.This value is much smaller than the change in August 2023,excluding the influence of water accumulation.④ Earthquake anomaly:The evaluation of earthquake prediction efficiency shows that R>R0,indicating that short-term horizontal changes have a higher credibility as earthquake anomalies;The anomalies were validated using measurements of soil gas Rn and H2 concentrations across faults,and it was considered that the accelerated rise of short levels is a seismic geophysical anomaly during the forecast period,occurred a ML 4.0 earthquake in Hebi,Henan Province on September 10,2023,corresponding to this short leveling anomaly.This case provides a reference basis for the abnormal determination of short leveling items and earthquake tracking research under conditions of significant environmental interference.
short leveling across faultsirregular load simulationquantitative analysissoil gas concentrationearthquake anomaly determination
万方数据
维普
