A. J. Sutton T. Elias M.P. Doukas T.M. Gerlach K.A. McGee 2006 <p class="Para">We report the results of two soil CO₂ efflux surveys by the closed chamber circulation method at the Puhimau thermal area in the upper East Rift Zone (ERZ) of Kilauea&nbsp;volcano, Hawaii. The surveys were undertaken in 1996 and 1998 to constrain how much CO₂ might be reaching the ERZ after degassing beneath the summit caldera and whether the Puhimau thermal area might be a significant contributor to the overall CO₂ budget of Kilauea. The area was revisited in 2001 to determine the effects of surface disturbance on efflux values by the collar emplacement technique utilized in the earlier surveys. Utilizing a cutoff value of 50 g m⁻² d⁻¹ for the surrounding forest background efflux, the CO₂ emission rates for the anomaly at Puhimau thermal area were 27 t d⁻¹ in 1996 and 17 t d⁻¹ in 1998. Water vapor was removed before analysis in all cases in order to obtain CO₂ values on a dry air basis and mitigate the effect of water vapor dilution on the measurements. It is clear that Puhimau thermal area is not a significant contributor to Kilauea's&nbsp;CO₂ output and that most of Kilauea's&nbsp;CO₂ (8500 t d⁻¹) is degassed at the summit, leaving only magma with its remaining stored volatiles, such as SO₂, for injection down the ERZ. Because of the low CO₂ emission rate and the presence of a shallow water table in the upper ERZ that effectively scrubs SO₂ and other acid gases, Puhimau thermal area currently does not appear to be generally well suited for observing temporal changes in degassing at&nbsp;Kilauea.</p> application/pdf 10.1007/s00024-006-0036-z en Springer Puhimau thermal area: a window into the upper east rift zone of Kilauea Volcano, Hawaii? article