Magnetotelluric investigation in West Greenland - considering the polar electrojet, ocean and fjords

A magnetotelluric survey has been conducted in North West Greenland, with the purpose of investigating the subsurface. The results of two processing techniques are presented, a single station robust processing and a multiple station processing. The multiple station processing tries to eliminate data originating from other sources than the plane wave by removing incoherent noise between stations and selecting time periods from an eigenvalue criteria. It is successful for periods below 55 s, but has to undergo further investigation at longer periods. The two processing techniques show similar results, however the multiple station technique improves the data quality around 1 s compared to the single station technique. Different challenges are connected with the survey location, where ocean and fjord systems have a large impact on the transferfunctions. A 3D model study of the impact of fjords on induction arrows is presented, illustrating the importance of including these in magnetotelluric modelling. This informationis included in the 3D modelling of the magnetotelluric survey in Greenland, together with the bathymetry of the ocean. The modelling shows that the impact from the fjords and ocean heavily dominates the signal, making it difficult to differentiate any geology in the subsurface.