CO2 Release in West Bohemia: Preparatory Experiments to remotely detect thermal anomalies

Abstract

In Western Bohemia (Czech Republic) and parts of the Vogtland and of the Oberpfalz (Germany) frequently earthquake swarms occur. Furthermore the region is characterised by large numbers of CO2-rich springs and mofettes (gas vents) spread over an area of a few thousand km2. Survey and mapping of these CO2 emanations in conjunction with ongoing geophysical investigations will contribute to the understanding of the earthquake/fluid dynamics interrelation. It is proposed to apply airborne infrared imaging technology to detect soil and perhaps also water surface thermal anomalies caused by emerging CO2. A low effort experiment was performed to investigate the feasibility of the method. Pressurised air was lead into the ground and released in some depth via a metal lance. The thermal effect at the surface was monitored by an infrared camera over several hours under varying meteorological conditions. Pronounced thermal anomalies were found at the regions of the gas emanation. The observations reveal that thermal contrast will depend on diurnal, seasonal and weather influences and very favourable conditions for airborne detection can be expected to occur. Investigations are going on.