摘要
利用大地电磁测深技术探测了云南玉溪盆地的电性结构及可能的断裂构造分布。在与地质构造近垂直的方向,布设了两条测线进行大地电磁观测,应用Rebocc二维反演方法获得了玉溪盆地两条测线的视电阻率剖面。结果显示,低阻体厚度的变化趋势与盆地第四系沉积层平均厚度的变化类似,在盆地西侧,厚度较深,高阻和低阻界面变化较陡。自西向东,低阻体厚度逐渐减小,高低阻界面变化趋势趋缓。总体来说,低阻体厚度比已有资料给出的沉积层厚度要深,导致这一结果的原因一方面可能是盆地沉积层厚度在不同的区域变化较大,另一方面也可能和沉积层下的岩层富含水资源有关。
Magnetotelluric survey has been carried out in the Yuxi basin, Yunan Province, to detect the electrical structure and the location of possible faults in the basin. The survey along two lines, which are nearly perpendicular to the geologic strike, has been performed. Apparent resistivity along these two profiles is inverted by Rebocc inversion method. Results show that the variety of the over layer thickness with low resistivity is similar with the thickness of the Quaternary sediment. In the west of the basin, the layer thickness with low resistivity is large and the interface between low and high resistivity varies abruptly. From west to east, the thickness reduced gradually. Generally speaking, the thickness of the structure with low resistivity is larger than the Quaternary sediment thickness. This suggests that the thickness of the Quaternary sediment has a significant change at different area in the basin. On the other side, such phenomena may also relate to the rich water resource in the rock layer beneath the sediment.
出处
《震灾防御技术》
2012年第4期357-366,共10页
Technology for Earthquake Disaster Prevention
基金
中国地震局地球物理研究所基本业务费专项资助(DQJB11C17)
关键词
玉溪盆地
MT测深
电性结构
Yuxi basin
MT sounding
Electrical structures
