Imaging Rainfall Infiltration Processes with the Time-Lapse Electrical Resistivity Imaging Method

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• 作者：Gang Zhang ; Gui-Bin Zhang ; Chien-chih Chen ; Ping-Yu Chang…
• 刊名：Pure and Applied Geophysics
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：173
• 期：6
• 页码：2227-2239
• 全文大小：9,061 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geophysics and Geodesy
  
• 出版者：Birkh盲user Basel
• ISSN：1420-9136
• 卷排序：173

文摘

Electrical Resistivity Imaging (ERI) was carried out continuously for 10 days to map the subsurface resistivity distribution along a potentially hazardous hillslope at the Jieshou Junior High School in Taoyuan, Taiwan. The reliability of the inverted resistivity structures down to about 25 m depth was examined with synthetic modeling using the same electrode arrangements installed on land surface as in field surveys, together with a DOI (depth-of-investigation) index calculated from the ERI data. The subsurface resistivity distribution is consistent with results from well logging. These ERI recordings were taken daily and provided highly resolved imagery of the resistivity distribution underground and illustrated the dynamical fluid-flow behavior due to heavy rainfall infiltration. Using Archie’s law, the resistivity distribution was transformed into a map of relative water saturation (RWS), which is strongly correlated with the rainfall infiltration process. We then found that the averaged RWS is significantly correlated with daily precipitation. Our observations indicate that time-lapse ERI is effective in monitoring subterraneous rainfall infiltration; moreover, the preferential flow paths can be delineated according to the changes in averaged RWS derived from the ERI data.KeywordsElectrical resistivity imagingdepth-of-investigationArchie’s lawrainfall infiltrationpreferential path