We generalized the QL approach to the time domain. As a result, we developed a new method of 3-D EM geophysical data forward modeling and inversion in the time domain. The developed QLTD inversion method and the computer code have been tested on several synthetic models. Figure 1 shows one of the models. The distance between the two anomalies is about 420 m. Figure 1.
Stars show the position of the receivers.
Black lines show the mesh used for inversion. The receivers were located at the Earth's surface at the points of a regular 9 X 9 grid with 50 m separation between the next receivers. Every single cell of the mesh is 100m x 100m in size. The electromagnetic field in the model was excited by a horizontal loop located 10 km away from the model. The inverted area was covered by a homogeneous mesh consisting of 9 X 9 X 10 cells with every cell of a size of 50m x 50m x 50m.