Volcanic activity monitoring through Raspberry Pi-based photography

Their breakthrough lies in detecting sulphur dioxide (SO2) emissions using affordable Raspberry Pi cameras, an advancement over the traditionally expensive SO2 cameras.

Volcanoes exhibit increased sulphur dioxide emissions when their activity intensifies. Monitoring these emissions is pivotal in predicting potential eruptions. SO2 has a unique characteristic of strongly absorbing ultraviolet (UV) and infrared (IR) light within certain wavelengths. These wavelengths, present in sunlight that penetrates the atmosphere, become key in detecting SO2. By employing a camera sensitive to these wavelengths and pointing it towards a volcanic region, the areas in the image appearing darker than the surrounding sky indicate the presence of SO2, absorbed from the UV and IR light.

Despite the effectiveness of SO2 cameras, their high cost has limited their installation, leading to inconsistent monitoring. Permanent installations are rare, with only significant volcanoes like Stromboli, Etna, and Kīlauea benefiting from continuous observation. This gap in consistent monitoring poses a challenge in both hazard assessment and volcanological research. Hence, a more economical method of SO2 photography is vital for both reducing risks and aiding researchers.

The innovation involves the adaptation of Raspberry Pi cameras, commonly used in digital photography. These cameras feature a Bayer filter, which typically filters out UV light. The researchers discovered that removing this Bayer filter, achievable by dissolving it with a substance similar to nail polish remover, enables the camera to capture images where SO2 presence is visible.

Additionally, the setup includes the WittyPi HAT, a real-time clock and power management system designed for Raspberry Pi. This system is instrumental in waking the volcano detector at specific times and allowing other components to conserve power when inactive. The integration of solar panels complements the system, facilitating continuous SO2 measurement during daylight.

The full research paper is available to read for free from frontiersin.org.