地磁加卸载响应比方法在上海及其邻区地震研究中的应用

Application of Geomagnetic LURR Method in Seismic Studies in Shanghai and its Adjacent Areas

本文运用2000—2010年上海佘山台和崇明台地磁场Z分量所计算得到的地磁加卸载响应比资料分析了近11年地磁加卸载响应比对上海及其邻区中小地震的预测分析效果,并对原有的预测指标体系进行了完善。分析结果表明:①地磁加卸载响应比值在大于3.4的异常情况下,对上海及其邻区的ML≥4.0地震预测有一定的指示意义;②两个台站的地磁加卸载响应比值随时间的整体变化趋势与上海及其邻区地震活动性的变化有较好的对应关系;③通过小波变换得到,地磁加卸载响应比值与该地区的地震活动性时间序列都存在4.5年的周期变化,且在该周期尺度上位相变化一致性较好。

Based on the vertical component Z of geomagnetic field observed respectively at the stations of Sheshan and Chongming for 11 years from 2000 to 2010, we calculated the values of the geomagnetic Load-Unload Response Ratio （LURR） and analyzed the seismic activity in Shanghai and its adjacent areas in the same period of time. We discussed the us- age of the value to predicting the earthquake and revised the original index system. The re- sults show that：① When the value of the LURR is greater than 3.4, there is a important implication for predicting M1≥4.0 earthquake in Shanghai and its adjacent areas; ② The overall trend of the values of the LURR is consistent with the variation characteristics of the seismic activity in this area; ③ the result of the wavelet transform indicates there is the same period about 4.5 year between the value of LURR and the seismic activity, and the phase variations are consistent in this period scale.