Recent Resistivity Measurements at Tokaanu-Waihi Geothermal Field

Abstract

New electrical resistivity measurements have been made in and around the Tokaanu-Waihi geothermal field to augment the existing data set. Measurements were made using several methods including traversing with Schlumbergerelectrode arrays where vehicle access is possible, equatorial dipole-dipole arrays operated boats in the south of Lake Taupo and magnetotelluric method on the slopes of Kakaramea and Tihia. The resistivity anomaly marking the field extends beneath the waters of Lake Taupo for about 1 north into Waihi Bay. On the high elevation ground to the west of Tokaanu the boundary is not sharply defined, although it appears to be high up the flanks of Tihia and there is a possibility that westward drainage of geothermal fluidsmay be the cause of lowresistivity to the west of Tihia.