4:45 PM - 5:00 PM
[HTT26-12] Characterization of the aquifer at Tottori sand dunes using NMR and GPR sounding
Keywords:Surface NMR, GPR, groundwater, Sand dune
GPR is usually applied for shallow subsurface investigation down to a few meters deep. Especially, the penetration depth will be shallower for the heterogeneous subsurface or clayey soils. However, the penetration depth goes deeper for the homogeneous thick sand deposit such as Tottori sand dunes. We completed the profile and the CMP surveys by 35 MHz antenna. The velocity of the EM wave is calculated from the CMP measurement and we created the depth profile using the calculated EM velocity. A clear reflection boundary is observed at around 29 to 30 m depth in the depth profile. The depth of the reflection agrees with the actual water level measured at several monitoring wells in the survey area.
The surface NMR enables us to obtain one dimensional result of water table and thickness of the aquifer, while GPR provides two dimensional image of water table. Therefore, combining the two methods must be an effective method to characterize aquifer in arid area.