2023年3月6日至4月28日榆树沟地震监测站洞体应变仪NE分量测值出现拉张速率变缓的异常趋势。现场异常核实后确定仪器状态正常，除附近水库水位上升外，环境无明显变化。通过绘制潮汐因子相对中误差曲线发现，仪器状态稳定，精度较高。进行R值检验发现，NE分量测值预报效能不高。为进一步判定异常变化来源，对比同站点其他仪器的数据情况，发现异常变化时段其他仪器测值也有相似速率变化，因此认为异常变化可能来自相同影响因素。采用气温、气压、洞温、水位等数据，利用相关性分析等方法，对可能存在的干扰因素进行对比分析。结果表明，从长趋势来看，洞体应变仪NE分量测值与水位间高度负相关，数据异常变化时段水位出现快速反向变化，此时洞体应变仪NE分量测值与水位间呈高度正相关，水位反向变化可能导致洞体应变仪NE分量测值拉张速率变缓，因此认为异常变化为水位干扰，而非地震前兆异常信号。
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.
2024,45(4): 68-74 收稿日期：2023-8-29
DOI：10.3969/j.issn.1003-3246.2024.04.009
基金项目：新疆维吾尔自治区地震局青年科学基金(项目编号:202314)
作者简介：毛玉剑(1992—),男,硕士,助理工程师,主要从事地球物理数据分析与仪器运维工作。E-mail:363108433@qq.com
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