Thermal Infrared Video Imagery Over the Rotorua Geothermal Field

Abstract

Delineation and monitoring of surface thermal activity at geothermal development sites and in tourist and urban areas is important for both planning and safety reasons. Because the standard methods for such work are time consuming, and often impractical, we have been developing helicopter-borne video thermal infrared scanner techniques. In a single 2-hour survey, a total area of 15-20 can be covered at a ground resolution of 1-2 The results obtained at Rotorua the value and power of the video data capture method, which provides real-time monitoring and the ability to store large quantities of readily accessible continuous imagery. We have also established an image processing facility which allows the imagery to be digitized for analysis by powerful image techniques. We have been able to accurately map thermal features in relatively inaccessibleareas, detect thermal water flowing through open and covered drains and thermal inflows to streams and lakes, detect hot spots in sealed roads and carparks constructed over thermal areas, and establish baseline data to compare with surveys formonitoring changesin surface activity.