A Thermal Area Beneath Lake Rotomahana Outlined by Sediment Temperature Measurements

Abstract

Temperature measurements made at a depth of 1 in the sediments at the bottom of Lake Rotomahana in October 1992 showed elevated temperatures in the south-western half of the lake and normal temperatures in the northeastern half. Temperatures greater than 1 above bottom water temperature occur over an area of 4.3 which is just over half of the lake: Within this anomaly, temperatures of greater than 5 above bottom water temperature occur in two areas, one in the west which is contiguous with the thermal activity on the shore, and the other in the southern part of the lake which appears to be a separate entity. The 1 m temperature measurements confirm the existence of a significant area of thermal activity beneath Lake Rotomahana.