Transient response characteristics of central loop configuration on seafloor
LIU Chang-sheng1,2 LIN Jun1,2 ZHOU Feng-dao1,2(1.College of Instrumentation Science and Electrical Engineering,Jilin University,Changchun Jilin 130061,China; 2.Key Lab of Geo-Exploration and Instrumentation of Ministry of Education,Jilin University,Changchun Jilin 130061,China)
The central loop is a typical antenna configuration in the transient electromagnetic detection on land. The transient response characteristics of this antenna configuration on seafloor are analyzed,and are compared with those in terrestrial environment. By comparison of the transient responses for different seafloor conductivity,the resolving power of the central loop to seafloor conductivity is studied. The influence of seawater depth and configuration size on transient responses and resolving power is also discussed. The results show that the central loop has good resolving power to the conductive seafloor,but poor one to the resistive seafloor. In the deep sea with conductivity of 3.2 S/m,the central loop of 2 m radius can resolve the seafloor whose conductivity is not smaller than 0.1 S/m. Decreasing the water depth can improve the resolving power to resistive seafloor at late time,and increasing the configuration size can improve the resolving power to resistive seafloor at early time. However,the extent of improvement is limited.