内蒙、甘、宁某些地区地球上部电导率分布的横向变化特征

ON THE LATERAL CHANGE CHARACTERISTICS OF CONDUCTIVITY DISTRIBUTION OF EARTH'S CRUST AND UPPER MANTLE IN SOME REGIONS OF NEIMENG, GANSU, NINGXIA

摘要:

这篇文章给出了内蒙、甘肃、宁夏某些地区的大地电磁测深结果。这些结果显示出,在地震带内地壳和上地幔电导率分布的横向变化是很明显的,而在比较稳定的鄂尔多斯地台内电导卑分布的横向变化较小,地壳和上地幔的电导率结构比较简单。基于这些结果发现,上部地壳(10-15公里)低阻层在大震震中区较为发育,这可能与大震有关。我国西北地区已有的大地电磁测深结果显示出,莫霍面並不是一个清楚的电性分界面,而某些地区的地壳中部低阻层似乎与康拉界面相应,这就使得后者成为一个明显的电性分界面。

Abstract:

This paper has given the MTS results in some regions of Neimeng, Gansu, Ningxia. It further demonstrates the conclusion about the presence of the anomaly low resistivity layer in the median earth crust of the seismic zone. It also shows that in the northern section of the South-Northern Seismic Belt the first low resistivity layer in upper mantle appears the zonal lift.
These results show that in the seismic zone the lateral changes of electrical distribution in the earth's crust and upper mantle are very remarkable, in the more stable Eerduosi Platform the lateral changes of conductivity distribution are less, and the electrical construction of the. earth's crust and upper mantle is simpler.
On the basis of these results it is found that a low resistivity layer in the upper earth's crust(~10-15km) appears clear in centrum regions of the stronger earthquakes, probably, it is related to stronger earthquake. The MTS results in Northwestern China show that M-interface is not a clear electrical interface, but the anomaly low resistivity layer in median earth's crust of some regions seems to be relative to C-interface, then it becomes a clear electrical interface.