新疆地震活动区的地磁观测与研究

新疆地区是中国最活跃的地震区之一.为了监测新疆地区潜在的强烈地震,2003年在该地区建立了N和S两个地磁测网并进行了地磁三分量测量.在N和S两个测网所选建的51个测点周围环境良好,地磁梯度小,适宜地磁测量.在野外测量中,使用性能稳定可靠的G-856磁力仪、DI磁力仪与GPS仪器,应用GPS测定方位角,DI磁力仪测量地磁偏角D与倾角I,G-856磁力仪测量总强度F.应用新疆地区乌鲁木齐与喀什地磁台站的资料,分别通化了N和S两个测网的地磁测量资料.该地磁通化值的平均标准偏差σ为:F的σf=0.20 nT;D的σd=0.06′;I的σI=0.03′,表明地磁测量资料准确可靠.根据上述地磁测量资料,应用精度高的spline方法,得到了N与S测网地磁场及其异常场的分布.结果表明,该地磁场及其异常场的分布,可以准确地描述N与S测网的地磁场及其地磁异常场.该地磁分布为今后在新疆地区的震磁研究与地震监测提供了良好的地磁参考场.

Geomagnetic observation and research in seismic active area of Xinjiang, China

The Xinjiang area is one of the most active seismic regions in China. In order to monitor the potential strong earthquakes in the Xinjiang area, two geomagnetic networks N and S were set up and the geomagnetic three component survey was carried out in 2003. In the field survey, the geomagnetic declination D, the inclination I and the total intensity F were measured. The geomagnetic survey data were reduced using the data at geomagnetic observatories in Xinjiang area. The mean standard deviations a of the geomagnetic reduced values are; σf=0.20 nT for F; σd =0.06' for D; σI= 0.03' for I. It shows that the geomagnetic surrey data are reliable and accurate. Based on the geomagnetic survey data in 2003, the distribution of the geomagnetic field and its anomalous field in the networks N and S was obtained and analyzed by using the spline method. The geomagnetic distribution can provide a good geomagnetic reference field for seismomagnetic research and earthquake monitoring in the Xinjiang area in the future.