Electromagnetic induction in the Vancouver Island region - field station and analogue model results.

Abstract

The results of geomagnetic measurements at field stations on Vancouver Island, British Columbia, and the nearby mainland are found to be in close agreement with measurements for a laboratory analogue model which employs a horizontal inducing field over a simple model including only the conducting ocean and a uniform earth. A transfer function and hypothetical event analysis of the field station measurements is used to compare field station and an alogue model vertical magnetic fields. The field station results show that for frequencies greater than -0.0006Hz (30min period) the fields are strongly affected by channelling of telluric current in the seawater channel between the island and the continent. As well, this study demonstrates that, for a coastal region, model studies can aid in selecting magnetotelluric stations minimally affected by the coast, and thus optimum for studying the tectonics of the region.