Magnetotelluric imaging of upper‐crustal convection plumes beneath the Taupo Volcanic Zone, New Zealand

Abstract

Broadband MT (magnetotelluric) data were recorded that form an array of measurements at the south‐eastern margin of the TVZ (Taupo Volcanic Zone), in the central North Island of New Zealand. These array data are used to investigate mechanisms by which the TVZ's extraordinarily high heat flux is transported to the surface. Taken together with seismological data, these MT data show compelling evidence that support a model of hydrothermal convection within the brittle (upper ∼6–7 km) part of the crust. Both 2‐D and 3‐D inversion models of these MT data show vertical low‐resistivity zones that connect surface geothermal fields to an inferred magmatic heat source that lies below the brittle‐ductile transition.