Affordable Access

Access to the full text

Features of Instability in Solving the Inverse Problem of Vertical Electrical Sounding for Precision Monitoring

Authors
  • Bobachev, A. A.1, 2
  • Deshcherevskii, A. V.2
  • Sidorin, A. Ya.2
  • 1 Moscow State University, Moscow, 119991, Russia , Moscow (Russia)
  • 2 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, 123242, Russia , Moscow (Russia)
Type
Published Article
Journal
Seismic Instruments
Publisher
Pleiades Publishing
Publication Date
May 25, 2021
Volume
57
Issue
3
Pages
302–320
Identifiers
DOI: 10.3103/S0747923921030038
Source
Springer Nature
Keywords
License
Yellow

Abstract

AbstractWhen solving many geophysical problems, vertical electrical sounding (VES) monitoring is used on stationary multielectrode installations. The resulting time series of observations can be considered as the VES profile (set of markers), deployed not in space, as with profile soundings, but in time. When solving the VES inverse problem for precision monitoring data on a stationary multielectrode VES array, the effect of a high-amplitude antiphase change in the resistivity of adjacent layers with time was discovered. This behavior is physically unlikely. To clarify the causes of this phenomenon, synthetic VES profiles, similar to real ones, were studied. In each layer of the model section, the law of the change (along the profile) in resistivity with time was set and synthetic curves of apparent resistivity were calculated. Then the VES inverse problem was solved. In this case, the same algorithms were used as for the experimental series. The obtained solutions were compared with the original synthetic resistivity profiles, which made it possible to analyze errors in the solution. The results showed that the effect of the antiphase change in resistivity of adjacent layers of the section (the swing effect in solving the inverse problem) is not associated with real changes in resistivity. It arises due to the special structure of the landscape of the discrepancy due to the equivalence in resistivity. This feature is not taken into account by standard algorithms for solving the inverse problem and can lead to rather large errors if no special countermeasures are taken. When monitoring a geoelectric section, increased requirements are imposed on the accuracy of solving the VES inverse problem. The required accuracy cannot be achieved with commonly used inversion algorithms. It is necessary to develop special algorithms for selecting a solution to the inverse problem that suppresses swing.

Report this publication

Statistics

Seen <100 times