Verification of cave body strain gauge observation anomaly at Yushugou Seismic Station
From March 6 to April 28,2023,the NE component of cave strain gauge at Yushugou Seismic Station showed an abnormal trend of slowing tensile rate.After on-site anomaly verification,it was determined that the instrument was in normal condition.There was no obvious change in the environment except for the rise of water level in the nearby reservoir.By drawing the relative mean square error curve of tidal factor,it was found that the instrument was stable and the accuracy was high.The R value test showed that the NE component prediction was inefficient.In order to further determine the source of abnormal change,compared with the data of other instruments at the same site,it was found that other instruments also had similar rate changes during the abnormal change period.Therefore,it is believed that the abnormal change may come from the same influencing factor.Based on the data of air temperature,air pressure,cave temperature and water level,the possible interference factors are compared and analyzed by correlation analysis and other methods.The results show that the NE component of the cave strain gauge is highly negatively correlated with the water level in the long trend.During the abnormal change period of the data,the water level changes rapidly in the opposite direction.At this time,the NE component of the cave strain gauge is highly positively correlated with the water level.The reverse change of the water level may lead to the relaxation rate of the NE component of the cave strain gauge.Therefore,it is considered that the abnormal change is the water level interference,not the earthquake precursor abnormal signal.
cavity strainabnormal verificationrelative median error of tidal factorR value test
万方数据
维普
