A magnetotelluric survery near Creston, British Columbia
In October of 1988, magnetotelluric data in a frequency band 0.001 to 100 Hz were recorded from six diamond necklace array stations along a 30 km profile crossing the Kootenay River in southeastern British Columbia, Canada. Four stations are on the west side of the river, equally separated by 1 km; a fifth station is about 5 km east of the river; the sixth station is about 25 km east of the river. These data have been modelled by both one-dimensional inverse techniques and two-dimensional forward fitting. The results indicate the following: There is a low electrical resistivity basement underneath all six stations. The conductive basement under the four western most stations has a resistivity of about 1Î© Â· m and is located at a depth of 4Â±0.5 km. Just east of the river, the conductive basement. has about the same resistivity as that to the west but at a depth of about 8Â±1 km. Below the most eastern station, the resistivity of the conductive basement is about 4Î© Â· m and about 2 km deep. There is an electrical anomaly between the four western most stations and the station east of the river. This may be a consequence of the Purcell Trench Fault; in other words, this nearly-vertical fault may be just east of the river where a geological contact exists.