Construction And Preliminary Application Analysis Of Temperature Stress Intensive Observation Array

Temperature and stress are important physical parameters for earthquake precursor observation,which can reflect the thermal state and dynamic action of the earth,as well as the process of earthquake preparation and occurrence.The observation data of continuous temperature stress monitoring are of great significance in many aspects of earth science and provide basic observation data for earthquake prediction and scientific research in related disciplines.Due to the high cost of instruments required by the existing temperature stress observation mode and the difficulty of constructing measurement points,the spatial density of temperature stress observation stations is low,especially the density of observation stations around deep and large faults and key earthquake monitoring and protection areas is seriously low,and the earthquake monitoring ability is insufficient.Based on the low-cost,portable and easy-to-install integrated temperature stress measurement sensor developed by the National Key RESEARCH and development Program,this paper takes the southern section of Xiaojiang fault zone as the monitoring area to carry out the construction of temperature stress intensive observation array,observation data quality evaluation and preliminary application analysis,and mainly carries out the following studies:(1)The construction scheme of low cost target downstage array measuring point is studiedCombining with local geological environment,under the rapid economic goals,the scheme of temperature and pressure of buried:borehole diameter not less than install auxiliary sensors and maximum diameter,drilling depth to local crust under normal temperature with depth,sensors installed to the scheduled depth,after more than 30 cm with quartz sand,or concrete landfill to sensor,and backfilling operations.Based on this scheme,the world’s largest temperature stress intensive observation station array with 110 observation points spaced 10km apart is constructed.(2)To evaluate the effectiveness of array observationBased on the observation data of 110 observation points in the constructed temperature and stress intensive observation array for more than 3 months,the observation efficiency of the array is evaluated.The results show that:The array runs normally,and the AD hoc network communication can meet the demand of realtime data transmission,and the transmission is stable.The data continuity rate can reach more than 99%.The low noise and significant diurnal variation of stress observation data indicate that the construction scheme of temperature and stress intensive observation array is feasible and can meet the needs of long-term continuous observation.The observation data reflect the actual state of rock temperature and pressure,and can provide reliable observation data for earthquake precursor extraction.The observation array has low construction cost,fast construction speed,simple and flexible network structure and easy realization,which can effectively meet the needs of temperature stress observation in local area and improve the spatial and temporal resolution of temperature stress observation data in monitoring area.It can provide technical support and application demonstration for the construction of intensive comprehensive observatory array in other key monitoring areas.(3)The change of temperature stress of the array is preliminarily analyzedThrough the preliminary analysis of the temperature and stress observation data generated by the array,we can get the normal observation condition without earthquake:Observation data of rock temperature:(1)There is no significant correlation between artesian well and rock temperature at observation points in short period(diurnal variation,three-day variation)and long period trend.(2)There is no significant correlation between non-artesian Wells and the changes of rock temperature in short period(diurnal variation,three-day variation)and long period trend.(3)The temperature data of the array itself has no obvious regular change with time.(4)The array temperature data is not affected by the surface temperature.(5)The array temperature data is not affected by the fault zone.Through the preliminary analysis of stress observation data.Rock stress observation data:① The array stress data itself has no obvious regular change with time.(2)The array stress data is not affected by the fault zone.Through the joint analysis of rock temperature stress.① Short period:there is no correlation between the temperature at the observation point and the short period of stress(daily variation and continuous 3-day variation).(2)Long period:there is no correlation between the temperature at the observation point and the short period of stress(monthly variation,continuous variation of three months).