Three‐year decline of magmatic CO 2 emissions from soils of a Mammoth Mountain Tree Kill: Horseshoe Lake, CA, 1995–1997

• Published in: Geophysical research letters Vol. 25; no. 11; pp. 1947 - 1950
• Main Authors: Gerlach, Terrence M., Doukas, Michael P., McGee, Kenneth A., Kessler, Richard
• Format: Journal Article
• Language: English
• Published: 01-06-1998
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/98GL01298

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.