caa a22 4500 477047823 CHVBK 20180405111335.0 cr unu---uuuuu 170330e19960801xx s 000 0 eng 10.1007/BF00878844 doi (NATIONALLICENCE)springer-10.1007/BF00878844 Poddar M. National Geophysical Research Institute Hyderabad, Andhra Pradesh, India aut Grounded-source transient E -field modeling of a shallow resistive layer with 3-D inhomogeneity [Elektronische Daten] [M. Poddar] There is growing interest in the use of transient electromagnetic (TEM) sounding for shallow geotechnical, environmental and groundwater investigations. Two commonly used transmitterreceiver configurations for TEM sounding are 1) loop-loop or its variation, in-loop configuration and 2) wire-loop configuration. The less common configuration of a horizontal electric dipole (HED) transmitter and receiver is treated in this study and called wire-wire configuration. Two important problems of shallow investigation in hard and soft rocks respectively are, defining 1) a fractured/fissured zone of medium resistivity, sandwiched between an overlying surface weathered rock of low resistivity and an underlying fresh compact rock of high resistivity and 2) a body of resistive sand buried in conductive clay. Lateral change in the middle layer resistivity is modeled by including a 3-D body of anomalous resistivity. The effect of perturbing the resistivity of the 3-D inclusion and the host middle layer for the wire-wire configuration is compared with that of the commonly used loop-loop configuration. The wire-wire configuration is found more sensitive to the model perturbations than the loop-loop configuration. 1-D inversion of synthetic 1-D data sets for the wire-wire configuration finds resolution and estimation errors to be less than 10 percent for all the model parameters. For 3-D models, 1-D inversion results give a resolution error of 10 percent or less for the depth to, resistivity and thickness of, the 3-D inclusion. The estimate is within 10 percent of the true value for the first parameter but 40 percent for the other two. Resolution as well as estimation of the basement resistivity is always very poor. Using the wire-wire configuration, it is theoretically possible to define a buried resistive layer and any lateral change in its resistivity, subject to the above limitations of 1-D inversion. However, the basement resistivity cannot be estimated with reasonable accuracy in the presence of a lateral inhomogeneity in the overlying layer. Birkhäuser Verlag, 1996 Grounded source nationallicence transient E -field modeling nationallicence resistive layer nationallicence 3-D inhomogeneity nationallicence resolution nationallicence pure and applied geophysics Birkhäuser-Verlag 147/3(1996-08-01), 551-566 0033-4553 147:3<551 1996 147 24 https://doi.org/10.1007/BF00878844 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00878844 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Poddar M. National Geophysical Research Institute Hyderabad, Andhra Pradesh, India aut NATIONALLICENCE 773 0- pure and applied geophysics Birkhäuser-Verlag 147/3(1996-08-01), 551-566 0033-4553 147:3<551 1996 147 24 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer