1. GEOPHYSICAL STUDIES SITE B GEOPHYSICAL STUDIES PROGRESS OSPER PROJECT SITE B BRUCE SMITH ROBERT BISDORF RAY HUTTON MARK TABACHECK ROBERT HORTON

2. GEOPHYSICAL METHODS USED DC RESISTIVITY SOUNDING obtain variation in electrical resistivity as a function of depth (to about 40 meters) ELECTROMAGNETIC PROFILING (EM31) obtain variation in electrical conductivity as a function of position (mapping lateral variations) 3 to 6 meters TOTAL FIELD MAGNETICS (not discussed) geologic mapping detect magnetic metallic objects (oil field pipes etc.) ELECTROMAGNETIC PROFILE (EM34…not discussed) depth to 40m but very noisy due to metallic pipes

3. DC RESISTIVITY

4. B SITE LOCATION DC RESISTIVITY SOUNDINGS

5. DC SOUNDINGS SITE B

6. ELECTRICAL CROSS SECTION SITE B RESISTIVITY (ohm meters) CONDUCTIVITY (millisiemens) ρ = 1000/σ(ms) σ(ms) = 1000/ρ 100 ohm meters = 10 ms

7. RESISTIVITY SOUNDING SITE B 100010010 CONDUCTIVITY WEATHERED BEDROCK

8. EM31 CONDUCTIVITY SURVEY Vertical dipoles depth ~4.5m Horizontal dipoles depth ~2.25m

9. EM31 HMD 2.25m depth map

10. EM31 VMD 4m depth map

11. EM31 HMD 4m 1960 Photo