Abstract: Because the study in line source 1-D forward is few until now,in this paper,all-time apparent resistivity is attained by horizontal component in electrical field.Theoretical calculations indicate that the horizontal electrical field component is one-to-one correspondence with resistivity,which made the definition of all-time apparent resistivity unique and reliable.The paper uses horizontal electrical field component to define the apparent resistivity and calculate with dichotomy.The calculation example shows that the apparent resistivity defined by this method can accurately reflect the information of the model.In the following research,for time domain with line source we found that at near area there are bad results from later period data.Because of the quick electromagnetic wave spread and decay,we have bad results from early stage data in far area also,and the detection depth increases with the transmitter-receiver distance.Finally,we obtain the relationship between maximum detection depth and transmitter-receiver distance by adding 5% random noise and comparing with the theoretical results.

Key words: time domain, all-time apparent resistivity, horizontal electrical field, dichotomy, random noise

摘要： 由于线源一维的正演国内外研究尚少,文中主要利用水平电场分量求取全区视电阻率。通过计算发现水平电场与电阻率之间是一一对应的关系,这使得定义全区视电阻率具有惟一性和可靠性。文中以水平电场定义视电阻率,然后利用二分搜索算法进行全区视电阻率求解。模型计算表明,该方法定义的全区视电阻率能较准确地反映地下电阻率信息。进一步研究发现:对时间域线源而言,在近区算不好晚期的数据,因为电磁波的传播、衰减很快,同样在极远区算不好早期的数据,而且探测深度是随收发距的增加而增大。最后,加入5%的随机噪声后与理论结果进行对比,得到了收发距与最大探测深度的关系。

关键词: 时间域, 全区视电阻率, 水平电场, 两分法, 随机噪声