Geophysical exploration in and around CTD

Applied Method GPR Electrical Resistivity Tomography (2D, 3D) Elastic Velocity (3D)

ERT Image (2D) Survey Area CTD Plug Survey Date Line1 Line2 Water conducting fracture End of CTD Plug 13MI40,41 Borehole (pressure monitoring) A~D Borehole for 3D tomography (Resistivity, Elastic wave) Conducted only on the same side as line1 Survey Date Before closure test July, 2014 After closure test (1st ) October, 2017 After closure test (2st ) February, 2018

Time lapse Resistivity Image(Line1) Before closure test (July, 2014) Pressure monitoring (13MI41) B E A A, B, E Borehole for tomography Fracture Water Conducting Fracture After closure test (1st, October, 2017) Pressure monitoring (13MI41) B E A After closure test (2nd, February, 2018) Pressure monitoring (13MI41) B E A End of CTD Plug

Time lapse Resistivity Image(Line2) Before closure test (July, 2014) Pressure monitoring (13MI40) A, B, E Borehole for tomography Fracture Water Conducting Fracture After closure test (1st, October, 2017) Pressure monitoring (13MI40) After closure test (2nd, February, 2018) Pressure monitoring (13MI40) End of CTD 水圧観測孔 Plug

Tomography Image (Resistivity, Elastic wave) Survey Area CTD Plug Line1 Line2 Target area Water conducting fracture End of CTD Plug 13MI40,41 Borehole (pressure monitoring) Wall on only 1 side (13MI40 side) 5 Boreholes Length of each borehole: 2m Survey Date Before closure test July, 2014

Tomographic Image (Resistivity) Scanned Volume: 1.75[m]*1.75[m]* 2.0[m] D C C End of CTD D Plug End of CTD Plug B A B Depth Wall Depth A Wall

Tomographic Image (P wave velocity) Scanned Volume: 1.75[m]*1.75[m]* 2.0[m] Plug End of CTD Wall Wall Depth Plug End of CTD Depth

Tomographic Image (Elastic wave attenuation) Scanned Volume: 1.75[m]*1.75[m]* 2.0[m] Plug End of CTD Wall Wall Plug End of CTD Depth Depth

GPR Image (GPR Reflection) Survey Area Both in inclined drift and CTD. Total length of measurement line: 505m (Not all profiles are shown in this slide) Survey Date Before closure test Several times before March, 2014

CTD (Wall) Configuration CMP Frequency 5～500MHz Wall (Left side) Wall (End of CTD) Plug End of CTD

CTD (floor) Configuration 0 offset Frequency 800MHz End of CTD

CTD (Both floor and Wall) Configuration 0 offset Frequency 800MHz Left wall Left wall Floor End of CTD Plug Floor Wall of End of CTD Floor Floor Right wall Right wall Right wall

Inclined (3D like profile) Floor (Inclined) 5Parallel survey lines Shaft Configuration 0 offset Frequency 800MHz Plug

Inclined (Right wall) Configuration 0 offset Frequency 800MHz Shaft Plug