Magnetotellurics in Scandes project. Multivariate analysis of high latitude magnetotelluric data
Abstract
Magnetotellurics in Scandes (MaSca) project focuses on the investigation of the lithospheric and upper mantle geolectric structure in transition zone from a stable Precambrian cratonic interior to a passive continental margin beneath the Caledonian Orogen and Scandes mountains in western Fennoscandia. Synchronous magnetotelluric array measurements were performed in the summers 2011-2012 by several research groups. All together data from 60 synchronous long period (LMT) and 200 broad band (BMT) sites were acquired. The array stretches from Lofoten,Norway to Kiruna,Sweden and further to the SE to Finland covering an area of 500x500 km in high latitudes region. LMT sites were occupied for about two months, while most of the BMT sites were measured during one day. Magnetotelluric measurements are known to be distorted by the source field effects at high latitudes caused by proximity of auroral electroject. We investigated the effect of the source on estimation of magnetotelluric transfer functions using multivariate approach. MV statistical methods can be applied to EM array data to reduce bias, improve signal-to-noise ratios, and provide better control over source effects and coherent noise contamination in estimates of EM transfer functions (TFs). Furthermore, within an array framework one is not limited to the classical uniform source magnetotelluric (MT) impedance and geomagnetic vertical field TFs, but can also include inter-station horizontal magnetic TFs which can be used to map anomalous induced currents, as well as hybrid impedance tensors between electric and magnetic fields from any pair of stations. Within the framework of the MV analysis several different approaches can be taken to estimation of these Tfs. In this work we present the results of MaSca data MV analysis and compare it to conventional remote reference results.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMGP33A1083S
- Keywords:
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- 1515 GEOMAGNETISM AND PALEOMAGNETISM / Geomagnetic induction