Puhimau Thermal Area: A Window into the Upper East Rift Zone of Volcano, Hawaii?

Abstract

We report the results of two soil CO 2 efflux surveys by the closed chamber circulation method at the Puhimau thermal area in the upper East Rift Zone (ERZ) of K" lauea volcano, Hawaii. The surveys were undertaken in 1996 and 1998 to constrain how much CO 2 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 CO 2 budget of K" lauea. 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 CO 2 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 CO 2 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 K" lauea's CO 2 output and that most of K" lauea's CO 2 (8500 t d )1 ) is degassed at the summit, leaving only magma with its remaining stored volatiles, such as SO 2 , for injection down the ERZ. Because of the low CO 2 emission rate and the presence of a shallow water table in the upper ERZ that effectively scrubs SO 2 and other acid gases, Puhimau thermal area currently does not appear to be generally well suited for observing temporal changes in degassing at K" lauea.

Diffuse Emission of Hydrogen from Poás Volcano, Costa Rica, America Central

“…Significant amount of gases are emitted in to the atmosphere by active volcanoes through visible manifestations such as plumes, fumaroles and hot springs, but nonvisible emanations through the surface environment known as diffuse degassing are also a significant source of deep-seated gases released to the atmosphere by active volcanoes (ALLARD et al, 1991;BAUBRON et al, 1990). During the last 20 years significant contributions of soil degassing studies related to volcanic activity have been reported (WAKITA et al, 1980;SATO and MCGEE, 1981;LOMBARDI and REIMER, 1990;CHIODINI et al, 1996CHIODINI et al, , 2001PÉREZ et al, 1996PÉREZ et al, , 2006D'ALESSANDRO and PARELLO, 1997;HERNÁ NDEZ et al, 2000, 2001a, b, 2003SALAZAR et al, 2001SALAZAR et al, , 2002ROGIE et al, 2001;GERLACH et al, 2001;AIUPPA et al, 2004;CARAPEZZA et al, 2004;FRONDINI et al, 2004;MCGEE et al, 2006). A few of these studies have been focused on hydrogen in the soil atmosphere (SATO and MCGEE, 1981;SATO, 1988;GIAMMANCO et al, 1998;HERNÁ NDEZ et al, 2000;MELIÁ N et al, 2003).…”

Testing the Use of Vegetation Indices as Indicators of Pre-Eruptive Volcanic Unrest at Kilauea Volcano, Hawaii

“…Additionally, the continued eastward migration of sparse vegetation land cover across the Chain of Craters Road was seen on the eastern side of the entire feature; this growth was described as "probable" in previous work [McGee et. al., 2006], but is certainly seen within this study.…”

“…Due to past known correlation with summit activity and intrusive events, the Puhimau feature was targeted as an important study area for this research. It has been previously described as a potential "window into the ERZ," both due to its close proximity to Kilauea's summit and degassing activity that coincides with intrusive events, as discussed earlier [McGee et. al, 2006].…”

“…The Puhimau geothermal feature is thought to have formed in 1936 due to degassing from an intrusion directly below the feature [McGee et. al., 2006].…”

“…al., 2006]. On the surface, soil temperatures have been highly elevated [McGee et. al., 2006;Torres, 2019], and the area releases anomalous amounts of CO2, H2S, and Mercury (Hg) compared to the surrounding region [Hinkle, 1978].…”