新疆呼图壁M_S6.2地震定点形变异常分析

通过对呼图壁MS6.2地震周围台站前兆资料的梳理、分析,其结果表明,榆树沟洞体应变趋势压缩、阜康水管仪趋势E倾、库尔勒水平摆趋势W倾、库尔勒断层趋势压缩等背景异常表明此区域应力处于不断积累状态;新源井下摆出现快速N倾、年变畸变中期异常;榆树沟水管仪出现速率加快,巴伦台钻孔应变出现大幅压性变化等短临异常。此次地震发生前前兆中期异常出现时间早,且距震中较远,而临震异常出现时间较为晚,距震中较近,中期和临震异常的空间演化呈现由外围向近场迁移的现象。

ANALYSIS ON DEFORMATION ANOMALIES BEFORE HUTUBI EARTHQUAKE WITH M_S6.2

Analyzing the precursory data of stations around Hutubi earthquake with MS6.2,the results showed:the trend anomalies indicated that the stress in this area was accumulating,which included the compressed trend of the trench extender in Yushugou,the east trend of water-tube in Fukang,and the west trend of horizontal pendulum and fault instrument in Korla.The medium-term anomalies of fast N-dip and annual distortion occurred in Xinyuan downhole,and the short-term and imminent anomalies of Yushugou water pipe meter were accelerated,and the borehole strain of Baluntai station was changed greatly.The mid-term precursory anomaly of the earthquake occurred earlier and farther from the epicenter,while the imminent anomaly occurred later and nearer to the epicenter.The spatial evolution of the mid-term and imminent anomaly showed a migration phenomenon from the periphery to the near field.