During May of 2021 and September of 2021, broadband magnetotelluric data were collected at 324 sites in a 10000 square Kilometer area. The survey was completed by scientist from the Finish Geological Survey (GTK) in cooperation with colleagues from Boliden, and summer students.
Station locations were carefully chosen away from busy roads and power lines to minimize cultural and electrical noise in the data. Horizontal electric fields were measured using non-polarizable electrodes placed in a four-electrode array. The dipole distances for each MT site were in the range of 80 to 100 meters with some exceptions corresponding to challenging site locations in the dense forests.
The surveys were made near a vibrant rural village, with several dairy farms and power cables around the area. Hence, station locations were carefully chosen away from busy roads and power lines to minimize cultural and electrical noise in the data. Horizontal electric fields were measured using non-polarizable electrodes placed in a four-electrode array. The dipole distances for each MT site were in the range of 80 to 100 meters with some exceptions corresponding to challenging site locations in the dense forests.
At the beginning of the work heavy snow covered the terrain, the measurements were made by skiing and the receiver was moved with a sled, but towards the end of the project, the snow had almost melted, and the water level was high in both swamps and ditches.
An unexpected change of plans, due to Covid restrictions, affected pre-planned timelines for some vital components of Finland magnetotelluric survey. Regardless of the restrictions it was possible to achieve the original survey goals, by extending the duration of the survey.