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An algorithm for fast 3D inversion of surface electrical resistivity tomography data: application on imaging buried antiquities
Author(s) -
Papadopoulos N.G.,
Tsourlos P.,
Papazachos C.,
Tsokas G.N.,
Sarris A.,
Kim J.H.
Publication year - 2011
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.2010.00936.x
Subject(s) - electrical resistivity tomography , geology , inversion (geology) , electrical resistivity and conductivity , tomography , economic geology , igneous petrology , environmental geology , regional geology , gemology , geophysics , mineralogy , hydrogeology , engineering geology , seismology , algorithm , volcanism , metamorphic petrology , computer science , geotechnical engineering , optics , tectonics , electrical engineering , engineering , physics
In this work a new algorithm for the fast and efficient 3D inversion of conventional 2D surface electrical resistivity tomography lines is presented. The proposed approach lies on the assumption that for every surface measurement there is a large number of 3D parameters with very small absolute Jacobian matrix values, which can be excluded in advance from the Jacobian matrix calculation, as they do not contribute significant information in the inversion procedure. A sensitivity analysis for both homogeneous and inhomogeneous earth models showed that each measurement has a specific region of influence, which can be limited to parameters in a critical rectangular prism volume. Application of the proposed algorithm accelerated almost three times the Jacobian (sensitivity) matrix calculation for the data sets tested in this work. Moreover, application of the least squares regression iterative inversion technique, resulted in a new 3D resistivity inversion algorithm more than 2.7 times faster and with computer memory requirements less than half compared to the original algorithm. The efficiency and accuracy of the algorithm was verified using synthetic models representing typical archaeological structures, as well as field data collected from two archaeological sites in Greece, employing different electrode configurations. The applicability of the presented approach is demonstrated for archaeological investigations and the basic idea of the proposed algorithm can be easily extended for the inversion of other geophysical data.