地电阻率小偶极装置观测的特性  

Observation Characteristics of Small Dipole Distance Device for Georesistivity

作　　者：文雯[1] 毛先进[1] WEN Wen;MAO Xianjin(Yunnan Earthquake Agency,Kunming 650224,China)

机构地区：[1]云南省地震局,昆明650224

出　　处：《华北地震科学》2022年第3期50-54,共5页North China Earthquake Sciences

基　　金：云南省地震局传帮带项目“地电阻率台站前兆信息获取能力评价及其改进方法研究”(C3-201705)。

摘　　要：从不同地层的影响系数和观测信号强度两方面,以不同类型地电结构的台站为例,研究了小偶极装置在地电阻率观测中的特性。研究显示,与对称四极装置相比:①对于下伏低阻型结构,小偶极装置更有利于压制浅部干扰、获取下部地层电阻率变化;②对于下伏高阻型结构,小偶极装置压制浅层干扰的能力与四极对称装置相当,但获取下部变化的能力具有明显优势;③对于均匀型结构,小偶极装置在压制浅层干扰的能力上有明显优势,获取下部变化的能力相当或有一定提高;④无论哪一类电阻率结构,小偶极装置的信号强度都低于对称四极装置,但在现有观测仪器技术水准下,采用偶极装置观测的信号强度是足够的。这表明在压制浅层干扰、反映下部介质电阻率变化方面,小偶极装置比对称四极装置有一定的优越性。In this paper,the characteristics of equatorial dipole device with small dipole distance in geo-resistivity observation are studied from the two aspects of the influence coefficients and signal strength in different strata in the observation area.The results show that compared with the symmetrical quadrupole device:①For the underlying low-resistance structure,the small dipole device is beneficial to suppress the shallow interference and obtain the lower stratum resistivity changes,②For the underlying high resistivity structure,the ability of the small dipole device to suppress shallow interference is close to that of the symmetrical quadrupole device,but the ability to acquire resistivity changes in the lower stratum is obviously better than that of the symmetrical quadrupole device,③For the uniform structure,the small dipole device is obviously superior to the symmetrical quadrupole device in suppressing the shallow interference,and the ability to obtain the resistivity changes of the lower stratum is close to that of the symmetric quadrupole device,④The signal strength of the small dipole devices is significantly lower than that of the symmetrical quadrupole device regardless of the type of resistivity structure,however,the signal strength of the small dipole device is sufficient for observation under the technical level of the existing observation instruments.

关 键 词：小偶极装置 对称四极装置 影响系数 信号强度 

分 类 号：P315.722[天文地球—地震学]