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Volcanic plume monitoring at Mijake-jima island (Japan)
   
 
JSPS
Research partially founded by JSPS
(Japan Society for the Promotion of Science)
 
 

A scientific cooperative research project was launched in 2005 between Istituto Nazionale di Geofisica e Vulcanologia – Sezione di Palermo (INGV-PA), Dipartimento Chimica e Fisica della Terra ed Applicazioni - Università di Palermo (CFTA-UNIPA) and Geological Survey of Japan - Advanced Institute of Science and Technology at Tsukuba (GSJ-AIST-Tsukuba). The principal investigators collaborating within the project are Dr. H. Shinohara (GSJ), Ing. G. Giudice, Dr. S. Gurrieri, Dr. M. Liuzzo and Dr. A. Privitera (INGV-PA), Prof. A. Aiuppa and Dr. E. Bagnato(CFTA-UNIPA).

Form the left to the right: E.Bagnato, S.Gurrieri, A.Aiuppa, H.Shinohara, G.Giudice, A.Privitera.
Form the left to the right: E.Bagnato, S.Gurrieri, A.Aiuppa, H.Shinohara, G.Giudice, A.Privitera.
Based on recent results obtained on the real-time observation of volcanic plume chemistry at Italian volcanoes (/monitoraggio/plumes/plumes.html; /sorveglianza/etna/plume.html), the target of the project was to promote further investigations both in technological and modelling aspects of volcanic plume research. At this aim, a new device for continuous volcanic plume monitoring was installed in August-September 2006 at Mijake-jima volcano in Japan. Mijake volcano, a basaltic strato-volcano located about 200 km South of Tokyo (Fig 2),
Fig. 2 – Site locations.
Fig. 2 - Site locations.
Fig. 3 - Main vent of the Miyake-jima volcano.
Fig. 3 - Main vent of the Miyake-jima volcano.
recently experienced a strong caldera-forming eruptive event in 2000 (Geshi et al. 2002), followed by the starting of gigantic volcanic gas SO2 emissions (Kazahaya et al., 2004). The volcano is currently undertaking passive degassing from the summit vent, the volatile composition of the plume having been investigated by Shinohara et al (2003a, b) (Fig 3).
Fig. 4 - Devices were installed on the summit of the edifice close to the South crater rim. The shelter was provided courtesy of Japan Meteorological Agency.
Fig. 5 - Example of data acquired on September 2th 2006 from the device installed on Mijake-jima volcano. Left scale and red line, background air-corrected CO2 concentrations (ppmVol) in the volcanic plume; right scale and blue line, SO2 concentrations (ppmVol) in the volcanic plume.
Fig. 4 - Devices were installed on the summit of the edifice close to the South crater rim. The shelter was provided courtesy of Japan Meteorological Agency.
Fig. 5 - Example of data acquired on September 2th 2006 from the device installed on Mijake-jima volcano. Left scale and red line, background air-corrected CO2 concentrations (ppmVol) in the volcanic plume; right scale and blue line, SO2 concentrations (ppmVol) in the volcanic plume.

The device, installed on the volcano summit (Fig. 4), consists of two multi-sensor gas analysers allowing the measurement of CO2, H2O, SO2 and H2S in the plume by combined use of IR spectrometers and specific electrochemical sensors (Aiuppa et al., 2005, 2006; Shinohara, 2005). The concentrations of the above gases in the plume are daily measured over four 1h acquisition periods (with a 1s acquisition frequency), data being captured and stored into a not-volatile memory. The acquired data (Fig. 5) will serve to (i) test the long-term stability of the sensors, (ii) to evaluate the background variations of volatile ratios (e.g., CO2/H2O, CO2/SO2, SO2/H2S) during the present quiescent phase (iii) to set up geochemical models of magmatic degassing on the volcano, useful for forecasting any future unrest.

The team at work at GSJ-AIST laboratory (Tsukuba)
The team at work at GSJ-AIST laboratory (Tsukuba)
   

References:
Aiuppa, A., Federico, C., Giudice, G. & Gurrieri, S. Chemical mapping of a fumarolic field: La Fossa Crater, Vulcano Island (Aeolian Islands, Italy). Geophys. Res. Lett. 32, No. 13, L13309, 10.1029/2005GL023207 (2005).
Aiuppa A., Federico, C., Giudice, G., Gurrieri, S., Liuzzo, M., Shinohara, H., Favara R., & Valenza, M. Rates of carbon dioxide plume degassing from Mount Etna volcano. J. Geophys. Res., in press (2006).
Geshi, N., T. Shimano, T. Chiba and S. Nakada, 2002, Caldera collapse during the 2000 eruption of Miyakejima Volcano, Japan, Bull. Volcanol., 64, 55-68.
Kazahaya, K., H. Shinohara, M. Odai, Y. Nakahori, H. Mori, K. Uto and J. Hirabayashi, Gigantic SO2 emission from Miyakejima volcano, Japan, caused by caldera collapse, Geology, 2004.
Shinohara, H., A new technique to estimate volcanic gas composition: plume measurements with a portable multi-sensor system, J. Volcanol. Geotherm. Res, 143, 319-333, 2005.
Shinohara, H., K. Kazahaya, G. Saito, K. Fukui, and M. Odai, Variation of CO2/SO2 ratio in volcanic plumes of Miyakejima: stable degassing deduced from heliborne measurements. Geophys. Res. Lett., 30 (5), 1208-1212, 2003a.
Shinohara, H., K. Fukui, K. Kazahaya, and G. Saito, Degassing process of Miyakejima volcano: implications of gas emission rate and melt inclusion data. In Melt inclusions in Volcanic systems edited by De Vivo, B., and Bodnar, B., Advances in Volcanology, 4, 147– 161, 2003b.

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