Remote sensing techniques can be used on large and small scales to aid mapping and monitoring,of geothermal surface features. Monitoring changes in geothermal surface features can provide some insight into the changing processes of geothermal fields caused by natural or anthropogenic sources. This study presents a geothermal-field scale survey using aerial thermal infrared (TIR) techniques to monitor changes in the lateral extent of geothermal surface features over time. Data from aerial TIR surveys conducted over the Rotorua Geothermal Field (RGF) (New Zealand) in 1990 and 2014 are compared to identify areas that may have changed between the two surveys. Differences in the area of geothermal surface features with temperatures greater than 28 degrees C and an area greater than 1 m(2) between 1990 and 2014 have been estimated for six zones of the RGF and used to infer the change over the entire RGF. Within error estimates, the Ngapuna, Ohinemutu, Kuirau, Arikikapakapa zones are calculated to have similar geothermal surface areas, while Sulphur Flats and Whakarewarewa zones show a decrease in the area Of geothermal activity between 1990 and 2014. Spatial patterns in changes between 1990 and 2014 are examined to determine potential near-surface geothermal processes. (C) 2016 Elsevier Ltd. All rights reserved.