[SVC48-P08] Flux measurements of carbon dioxide at Beppu geothermal area using a portable non-dispersive infrared (NDIR) gas analyzer
Keywords:Beppu, hot spring, carbon dioxide
Beppu geothermal area located on central Kyushu direction, Japan is situated in graben zone formed by tensional stress, and is generated by western active volcanoes of Mt. Tsurumi and Garan. These volcanoes supply geothermal fluids on the area. Allis and Yusa (1989) measured the temperature under 100 m depth in the area, and revealed two parts with high temperature. The high temperature areas are located along the faults of northern and southen parts. Mine (2006) measured CO2 flux in the northern part and showed high values along the Kannawa fault. Here, we tried to measure CO2 flux in the southern part around the Horita and Asamigawa faults.
We used a chamber method which is measurement of concentration rate of CO2 in the vessel covered on the ground, and estimated CO2 flux at about 200 sites. The obtained CO2 fluxes range in 0.07-66.1 g/m2-day. High values of 2.71-66.1g/m2-day are observed on hot spring flows underground reported by Yusa and Ohsawa (2000), suggesting that CO2 gases are released from hot spring flows underground and raise to ground surface.
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