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| Titel |
Methane concentration inside a submarine mud volcano examined through seismic velocity profiles |
| VerfasserIn |
Arata Kioka, Takeshi Tsuji, Hironori Otsuka, Juichiro Ashi |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139729
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| Publikation (Nr.) |
 EGU/EGU2017-3024.pdf |
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| Zusammenfassung |
| Mud volcanoes are considered to be among largest geological sources releasing hydrocarbon
gases into the atmosphere. Numerous studies have revealed their origins and compositions
from submarine mud volcanoes. A recent long-term observation at a submarine mud volcano
sheds light on that larger volume of methane gas than expected is escaped from
deep-water mud volcanoes, suggesting that the global methane flux from the seafloor
is likely underestimated. Yet, estimates of the gas amount inside mud volcanoes
have been still challenging, because of the difficulty of in-situ measurements. This
study provides a new model to bridge methane amounts and seismic velocities in
fluidized mud conduits of submarine mud volcanoes. This model is universally
applicable and enables estimates of methane concentration in the mud conduits,
using the seismic velocity profile derived from reflection/refraction seismic and/or
downhole logging data. In this study, (1) we examine our modeled results through
deep-drilling data obtained at mud volcanoes in the Olimpi mud field of the central
Mediterranean Ridge accretionary margin, to evaluate the difference between in situ methane
amounts and those calculated from our model, and (2) apply our model to the seismic
velocity profile derived from seicmic data to estimate the methane amount inside the
submarine mud volcano in the Nankai accretionary margin. Our scheme may provide an
opportunity to re-estimate the total methane flux from submarine mud volcanoes. |
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