Magnetotelluric Soundings Along a Transect of the CVR

Abstract

New broadband magnetotelluric soundings have been made along a transect of the to the south of Lake Rotorua where the CVR has a width of about Data from the eastern end of the line are strongly 2-dimensional in character and indicate an orientation of electrical strike that is consistent with the gross tectonic strike of the eastern margin of the CVR and Taupo Volcanic Zone. inversion of apparent resistivity and phase data fi-om the easternmost 5 sites yields a resistivity structure which is consistent with previous deep dc measurements and suggests that low resistivity exists to depths of at least and, below depth possibly extends further to the west than has previously been identified. In contrast data close to the western margin of the CVR is much more complex and exhibits 3-dimensional characteristics which suggest that the data may be influenced by the trending Hauraki Riftjust to the north of the western end of the transect.