Implications for eruptive processes as indicated by sulfur dioxide emissions from Kilauea Volcano, Hawai'i, 1979-1997

Kilauea Volcano, Hawai'i, currently hosts the longest running SO2 emission- rate data set on the planet, starting with initial surveys done in 1975 by Stoiber and his colleagues. The 17.5-year record of summit emissions, start ing in 1979, shows the effects of summit and east rift eruptive processes, which define seven distinctly different periods of SO, release. Summit emis sions jumped nearly 40% with the onset (3 January 1983) of the Pu'u O'o-Kup aianaha eruption on the east rift zone (ERZ). Summit SO2 emissions from Kil auea showed a strong positive correlation with short-period, shallow, calde ra events, rather than with long-period seismicity as in more silicious sys tems. This correlation suggests a maturation process in the summit magma-tr ansport system from 1986 through 1993. During a steady-state throughput-equ ilibrium interval of the summit magma reservoir, integration of summit-cald era and ERZ SO2 emissions reveals an undegassed volume rate of effusion of 2.1 X 10(5) m(3)/d. This value corroborates the volume-rate determined by g eophysical methods, demonstrating that, for Kilauea, SO2 emission rates can be used to monitor effusion rate, supporting and supplementing other, more established geophysical methods. For the 17.5 years of continuous emission rate records at Kilauea, the volcano has released 9.7 X 10(6) t (metric to nnes) Of SO2, 1.7 X 10(6) t from the summit and 8.0 X 10(6) t from the east rift zone. On an annual basis, the average SO2 release from Kilauea is 4.6 X 10(5) t/y, compared to the global annual volcanic emission rate of 1.2 X 10(7) t/y. (C) 2001 Elsevier Science B.V. All rights reserved.