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Three‐year decline of magmatic CO 2 emissions from soils of a Mammoth Mountain Tree Kill: Horseshoe Lake, CA, 1995–1997
Author(s) -
Gerlach Terrence M.,
Doukas Michael P.,
McGee Kenneth A.,
Kessler Richard
Publication year - 1998
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 - 10.1029/98gl01298
Subject(s) - mammoth , geology , hydrology (agriculture) , soil gas , soil water , tonne , environmental science , archaeology , soil science , paleontology , geography , geotechnical engineering
We used the closed chamber method to measure soil CO 2 efflux over a three‐year period at the Horseshoe Lake tree kill (HLTK)—the largest tree kill on Mammoth Mountain in central eastern California. Efflux contour maps show a significant decline in the areas and rates of CO 2 emission from 1995 to 1997. The emission rate fell from 350 t d −1 (metric tons per day) in 1995 to 130 t d −1 in 1997. The trend suggests a return to background soil CO 2 efflux levels by early to mid 1999 and may reflect exhaustion of CO 2 in a deep reservoir of accumulated gas and/or mechanical closure or sealing of fault conduits transmitting gas to the surface. However, emissions rose to 220 t d −1 on 23 September 1997 at the onset of a degassing event that lasted until 5 December 1997. Recent reservoir recharge and/or extension‐enhanced gas flow may have caused the degassing event.