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Magma degassing triggered by static decompression at Kīlauea Volcano, Hawai‘i
Author(s) -
Poland Michael P.,
Sutton A. Jeff,
Gerlach Terrence M.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039214
Subject(s) - geology , volcano , magma , summit , petrology , decompression , seismology , lateral eruption , rift zone , deflation , geochemistry , explosive eruption , rift , physical geography , tectonics , medicine , surgery , monetary policy , monetary economics , economics , geography
During mid‐June 2007, the summit of Kīlauea Volcano, Hawai‘i, deflated rapidly as magma drained from the subsurface to feed an east rift zone intrusion and eruption. Coincident with the deflation, summit SO 2 emission rates rose by a factor of four before decaying to background levels over several weeks. We propose that SO 2 release was triggered by static decompression caused by magma withdrawal from Kīlauea's shallow summit reservoir. Models of the deflation suggest a pressure drop of 0.5–3 MPa, which is sufficient to trigger exsolution of the observed excess SO 2 from a relatively small volume of magma at the modeled source depth beneath Kīlauea's summit. Static decompression may also explain other episodes of deflation accompanied by heightened gas emission, including the precursory phases of Kīlauea's 2008 summit eruption. Hazards associated with unexpected volcanic gas emission argue for increased awareness of magma reservoir pressure fluctuations.