3D ERT Monitoring of Levee Flooding Experiment Using Multi-current Transmission Technique
Y.Y. Yamashita, T. Kobayashi, H.S. Saito, T. Sugii, T. Kodaka, K.M. Maeda and Y.C. Cui
Event name: 23rd European Meeting of Environmental and Engineering Geophysics
Session: Geoelectrics and Electromagnetics - Instrumentation, Theory and Applications II
Publication date: 03 September 2017
Info: Extended abstract, PDF ( 4.78Mb )
Price: € 20
We conducted a field experiment to simulate levee overflow using a model bank. We built a small scale model bank and water pool for simulating water level rising at river levee. We also set equipment for artificial rainfall above the model bank. As one of monitoring measurements of model bank while rising water level and raining artificially, we conducted time-lapse ERT survey on this model bank for the purpose of capturing water infiltration inside the model bank. We set plural 2D survey lines to cover whole area of model bank. To realize fine time resolution ERT measurement of plural survey lines, we applied multi-current transmission instrument, which has 8 transmitters and 8 receivers. With this instrument, we can improve measurement efficiency by injecting current at plural current electrodes simultaneously. We conducted a set of measurement which has 3072 data at the interval of 20 minutes. We performed 2D and 3D resistivity inversion. We can capture the water infiltration into the model bank by fine time resolution ERT measurement. The brackish saline water worked as a good tracer of ERT measurement in this case. 3D inversion using 2D survey lines data contributed to understand the spatial distribution of resistivity time variation.