Resistivity methods - MT

Abstract

Magnetotellurics (MT) is a passive electrical resistivity method that probes the subsurface resistivity structure from a depth of a few tens of meters down to a depth of several tens or even hundreds of km. It is the only method that is capable of revealing the resistivitity at such a great depth. It is a passive method, using the magnetic variations of the geomagnetic field as its source. Contrary to active resistivity methods like, the geoelectrical methods where an injected current into the earth is the source and the TEM method where the source is a current loop. The basic knowledge of the MT method includes acquisition, processing and interpretation. There exits a variety of books and articles on the method which has developed greatly the last decades as the dynamical range in data recording has inceased and computer capacities as well. A book that covers the practical aspects of applying the magntotelluric technique should recommeded: Practical Magnetotellurics by Simpson and Bahr (2005). Making use of the internet is always a good idea. Take a look at the webside, MTnet which is an internet forum for the free exchange of programs, data and ideas, especially for scientist in noncommercial studies. The address for the web page is: www.mtnet.inf