The SO2 camera: A simple, fast and cheap method for ground-based imaging of SO2 in volcanic plumes

SO2
flux is widely monitored on active volcanoes as it
gives a window into the hidden, subsurface magma
dynamics. We present here a new approach to SO2 flux
monitoring using ultraviolet imaging of the volcanic plume
through carefully chosen filters to produce images of SO2
column amount. The SO2 camera heralds a breakthrough in
both our ability to measure SO2 flux at unprecedented
frequencies (2 Hz) and at unprecedented accuracy, thanks to
the application of correlation techniques to determine wind
speed directly from the images and the ability to measure
the whole profile simultaneously. In this paper we detail the
commercially available pieces required to construct the SO2
camera, introduce a retrieval scheme to determine SO2
amounts from the images and present results from a field
campaign in November 2005 on Sakurajima volcano, Japan.

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