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GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L12301, doi:10.1029/2006GL026223, 2006

Mauna Loa volcano is not a methane source: Implications for Mars

Steven Ryan

Mauna Loa Observatory, Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Hilo, Hawaii, USA


Edward J. Dlugokencky

Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA


Pieter P. Tans

Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, USA


Michael E. Trudeau

Mauna Loa Observatory, Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Hilo, Hawaii, USA


Abstract

Thirteen years of continuous atmospheric carbon dioxide and methane measurements at the Mauna Loa Observatory in Hawaii are used to determine the methane emission rate from the summit of Mauna Loa volcano. We find no measurable methane emissions coming from the summit area, with a 95% confidence upper limit of 9 t CH4 yr−1. Recent studies have detected 10 ppb CH4 in the Martian atmosphere, requiring emissions of about 300 t CH4 yr−1. Volcanic activity has been suggested as a source of abiogenic CH4 on Mars, either by magmatic degassing or reactions in hydrothermal fluids heated by a magma intrusion. The most recent lava flows on Mars (2 My ago) are on the Tharsis shield volcanoes, which may still be active. If Mauna Loa is a valid terrestrial analog, our findings suggest that volcanic activity is not a significant source of methane to the Martian atmosphere.

Received 6 March 2006; accepted 9 May 2006; published 22 June 2006.

Index Terms: 0370 Atmospheric Composition and Structure: Volcanic effects (8409); 6225 Planetary Sciences: Solar System Objects: Mars; 8450 Volcanology: Planetary volcanism (5480, 6063, 8148); 8485 Volcanology: Remote sensing of volcanoes; 8430 Volcanology: Volcanic gases.

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Citation: Ryan, S., E. J. Dlugokencky, P. P. Tans, and M. E. Trudeau (2006), Mauna Loa volcano is not a methane source: Implications for Mars, Geophys. Res. Lett., 33, L12301, doi:10.1029/2006GL026223.