Time-lapse Inversion of 2D Resistivity Monitoring Data

          ,  !" &' #$% * ()+ ,- ' /01 . '2  4 3 . ' 7 6 5 /01 .  #8 : *9 ;" ? A: @ BD4 C . E BC  @A  F.G H  I( J K7 .GI L" : M" , ( I NN" 7 IK .G O": M" 7 ( '4 P . R: KQ ? ? ? <= @A , ^KAbstract: The resistivity method has been used to image the electrical properties of the subsurface. Especially, this methodhas become suitable for monitoring since data could be rapidly and automatically acquired. In this study, we developeda time-lapse inversion algorithm for the interpretation of resistivity monitoring data. The developed inversion algorithmimposes a big penalty on the model parameter with small change, while a minimal penalty on the model parameter withlarge change compared to the reference model. Through the numerical experiments, we can ensure that the time-lapseinversion result shows more accurate and focused image where model parameters have changed. Also, applying the time-lapse inversion method to the leakage detection of an embankment dam, we can confirm that there are three major leakagezones, but they have not changed over time. Keywords: resistivity monitoring, time-lapse inversion, leakage detection