Determination of hydrothermal prospects in the geothermal region of paipa (Boyacá, Colombia), using remote sensing and field data

Abstract

Geothermal resources have been found with the help of conventional geological, geochemical, and geophysical techniques. However, in some cases, difficult access to research areas hinders its application, which in turn increases operating costs and restricts areas of exploration. Remote sensors with thermal infrared are an important tool in the exploration of geothermal resources due to the low cost and high efficiency in the study of large geographic areas. In this research, thermal images of remote satellite sensors are used and integrated with existing geological-geophysical information for the determination of exploratory prospects of hydrothermal vents in the geothermal region of Paipa, Boyacá. The satellite thermal images used are Landsat 7 ETM+ and Landsat 8 OLI/TIRS. Radiometric calibration, atmospheric correction, surface thermal emissivity calculation, a single-channel, and Split window algorithm were applied to retrieve the land surface temperature. Soil temperature, surface temperature, air temperature, relative humidity, atmospheric pressure, and thermal imagery of the geothermal manifestations were also used. The field data contributed to the correction of the thermal bands, and the soil temperature data helped to create a subsurface temperature map at one-meter depth. Once the primary and secondary data was available, in a GIS, an unweighted spatial model was implemented, which used four input indicators (satellite temperature index, soil temperature index, structural lineaments index, and iso-resistivity index), to determine the areas most likely to find geothermal fluids. Six areas of exploratory interest for the extraction of hydrothermal fluids were determined, of which two are already known, and the remaining four are proposed as prospects. The results allowed us to conclude that thermal remote sensors are a useful tool for the mapping of geothermal anomalies in the Paipa region, and by combining these anomalies with geological-geophysical information, it is possible to determine specific areas of exploration.