Thermal Infrared (IR) Camera Imaging for Ground-Based Remote Thermal Monitoring

Thermal Infrared (IR) Camera Imaging for Ground-Based Remote Thermal Monitoring
The infrared thermal imager NEC Thermo Tracer

Introduction

A thermal tracer camera (Thermo Tracer NEC TH7100) has been used in precise thermal investigations in the Nisyros caldera which monitor fumarolic and hot spring temperatures, as well as in the Solfatara fumarolic field and in the Vesuvius summit crater.

Three main advantages exist for the use of such an infrared imaging system for volcanic monitoring:

1. It is the ideal tool for volcanic monitoring in active but dormant volcanic craters with no access or dangerous access. The camera system registers any thermal anomaly (episodically or continuously) and sends the images to a control centre to be analyzed and interpreted. A test study at Vesuvius demonstrated clearly the validity of this technology. As a result, several units will be installed soon at this location to recognize directly any thermal anomaly in this most dangerous European volcano.

2. Infrared thermal imaging is a very useful tool for directly testing the surface thermal output derived as part of this project by heat flux measurements in the Nisyros caldera (i.e. Stefanos crater) and at the Solfatara fumarolic field.

3. In addition, thermal measurements with this camera systems in a rough topographic terrain allowed a significant reduction of atmospheric influences on calibration of the satellite LANDSAT 7 and ASTER thermal imaging. Thermal satellite images can then become a very useful surveying tool for early warning in volcano systems.

Fig. 31 Infrared thermal images recorded with portable NEC thermal tracer. Upper picture: Daylight digital image; lower picture: infrared thermal image of the Nisyros hydrothermal crater field, acquired before sunrise. Temperature variation 18 to 32°C. Swiss Federal Institute of Technology (ETHZ)
(Click on image to enlarge).

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