Continuous Resistivity Profiling (CRP) at Callahan Mine Site: May 2017 to July 2018

In May 2017 and July 2018, continuous resistivity profiling (CRP) surveys were collected in Goose Pond at the Callahan Mine site. CRP methods were used to characterize the resistivity of the water column and subbottom layers. For this investigation, 11 electrodes spaced 10 m apart and mounted in a streamer were towed behind the boat. The first two electrodes, closest to the boat, were used to inject current into the water and subbottom materials, and eight electrical potential measurements were made using the remaining nine electrodes in dipole-dipole configuration. With this system, a complete suite of measurements is collected every 2.8 seconds. Because the boat was moving at a slow rate of speed, a complete measurement is taken while the boat has moved about 3-5 m. In general, voltage measurements taken with larger electrode spacings extend deeper into the subsurface. The exact depth and resistivity is determined through a process of inversion. The raw CRP data are shared in this data release.