南北地震带大地电流分布与地震活动关系探讨

The spatial distribution of telluric currents and its relationship with earthquake activities in North-South Seismic Belt

利用中国南北地震带38个固定地电场台站观测数据,研究该区大地电流场流线和电流矢量的分布特点,分析了大地电流矢量场的涡度和散度,并联系动力学机制讨论了大地电流与南北地震带的关系,探讨地震活动与电流涡度时变的对应性。这是首次应用空间密度较高的地电场台站开展这方面的研究工作。结果表明:(1)大地电流线走向和汇聚特点与构造地块的运动特点具有某种一致性,在构造边界上大地电流矢量存在汇集及分异的现象;(2)大地电流汇聚和发散等现象与断裂构造相关,一般表现为流线沿断裂带走向汇集或发散,在断裂交错地区表现出较复杂的形态;(3)大地电流场涡度分布特点可作为大构造块体运移的电性指示,涡度随时间变化可能为某种地震前兆。

Using the data of 38 fixed geoelectrical stations along the North-South seismic belt in China,this paper discussed the relationship between earthquake activities and the time-varying of the vortex current,by studying the distribution of telluric current vector and the streamlines of the telluric current,combining with the vortex and divergence abnormal of the telluric current vector field,as well as taken the geological characteristics of the North-South seismic belt into consideration.The results show that（1）there is some coincidence of the distribution of the telluric current and the movement of the geological stock,which means that the telluric current lines may converge or diverge along the geological boundary;that（2）the convergence or divergence of the telluric current lines are related to the fault structure,and usually the lines converge or diverge along the fault zone,but they will be complex in the faults crossed zone;that（3）the distribution of the telluric current field vorticity can act as an electrical indicator of the large geological stock＇s movement,and the time-varying of the vortex may indicate the happening of the earthquake.