Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf
Since the last glaciation the Canadian Arctic Beaufort Shelf is subjected to marine transgression. From subaerial mean annual temperatures during terrestrial exposure of ≤ -20°C, thermal conditions changed up to present submarine bottom water temperatures near -1°C. While conditions during the Plioc...
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ftoceanrep:oai:oceanrep.geomar.de:53333 2023-05-15T14:25:58+02:00 Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf Grob, H. Riedel, Michael Krastel, Sebastian Bustamante Restrepo, J. Duchesne, M. J. Fabien-Ouellet, G. Jin, Y. K. Hong, J. K. 2021 https://oceanrep.geomar.de/id/eprint/53333/ unknown Grob, H., Riedel, M. , Krastel, S. , Bustamante Restrepo, J., Duchesne, M. J., Fabien-Ouellet, G., Jin, Y. K. and Hong, J. K. (2021) Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf. [Poster] In: 81. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG). , 01.03.-05.03.2021, Kiel (online) . info:eu-repo/semantics/closedAccess Conference or Workshop Item NonPeerReviewed 2021 ftoceanrep 2023-04-07T15:57:22Z Since the last glaciation the Canadian Arctic Beaufort Shelf is subjected to marine transgression. From subaerial mean annual temperatures during terrestrial exposure of ≤ -20°C, thermal conditions changed up to present submarine bottom water temperatures near -1°C. While conditions during the Pliocene favoured extensive formation of permafrost and gas hydrates, present occurrences are exposed to degradation due to the warmer climate. Today, submerged offshore permafrost is still responding to this thermal change. Ongoing degradation creates the potential of methane release of previously trapped biogenic gas within the relic permafrost and from gas hydrate dissociation. The mobilisation of methane and its possible release to the atmosphere plays a significant role in climate change. Yet, both the extent of permafrost and underlying gas hydrates is still poorly known. Here, we present seismic indicators for offshore permafrost and gas hydrates in 2D multichannel reflection seismic data acquired in the Canadian Beaufort Sea. Seismic lines that run from the shallow shelf towards deeper water show layer-crossing reflections that become gradually shallower towards the north-west into deeper water. These reflections show an amplitude-varying characteristic and are phase-reversed. We first use shot gathers from a synthetic model based on the field seismic acquisition characteristics and borehole geophysical data to verify our general ability to detect permafrost-and gas hydrate-related reflections. The synthetic data were processed using the same data processing applied to the field data and reveal clear top and base of permafrost and gas hydrate reflections. With this encouraging result, we can exclude any potentially misleading processing artefacts in the field seismic data. We interpret the amplitude-varying, phase-reversed and layer-crossing reflections seen in the field data as seismic indicators for the base of permafrost and base of gas hydrates. In contrast to the synthetic data, top of permafrost and top of ... Conference Object Arctic Arctic Beaufort Sea Climate change permafrost OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Arctic Beaufort Shelf ENVELOPE(-142.500,-142.500,70.000,70.000) |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
unknown |
description |
Since the last glaciation the Canadian Arctic Beaufort Shelf is subjected to marine transgression. From subaerial mean annual temperatures during terrestrial exposure of ≤ -20°C, thermal conditions changed up to present submarine bottom water temperatures near -1°C. While conditions during the Pliocene favoured extensive formation of permafrost and gas hydrates, present occurrences are exposed to degradation due to the warmer climate. Today, submerged offshore permafrost is still responding to this thermal change. Ongoing degradation creates the potential of methane release of previously trapped biogenic gas within the relic permafrost and from gas hydrate dissociation. The mobilisation of methane and its possible release to the atmosphere plays a significant role in climate change. Yet, both the extent of permafrost and underlying gas hydrates is still poorly known. Here, we present seismic indicators for offshore permafrost and gas hydrates in 2D multichannel reflection seismic data acquired in the Canadian Beaufort Sea. Seismic lines that run from the shallow shelf towards deeper water show layer-crossing reflections that become gradually shallower towards the north-west into deeper water. These reflections show an amplitude-varying characteristic and are phase-reversed. We first use shot gathers from a synthetic model based on the field seismic acquisition characteristics and borehole geophysical data to verify our general ability to detect permafrost-and gas hydrate-related reflections. The synthetic data were processed using the same data processing applied to the field data and reveal clear top and base of permafrost and gas hydrate reflections. With this encouraging result, we can exclude any potentially misleading processing artefacts in the field seismic data. We interpret the amplitude-varying, phase-reversed and layer-crossing reflections seen in the field data as seismic indicators for the base of permafrost and base of gas hydrates. In contrast to the synthetic data, top of permafrost and top of ... |
format |
Conference Object |
author |
Grob, H. Riedel, Michael Krastel, Sebastian Bustamante Restrepo, J. Duchesne, M. J. Fabien-Ouellet, G. Jin, Y. K. Hong, J. K. |
spellingShingle |
Grob, H. Riedel, Michael Krastel, Sebastian Bustamante Restrepo, J. Duchesne, M. J. Fabien-Ouellet, G. Jin, Y. K. Hong, J. K. Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
author_facet |
Grob, H. Riedel, Michael Krastel, Sebastian Bustamante Restrepo, J. Duchesne, M. J. Fabien-Ouellet, G. Jin, Y. K. Hong, J. K. |
author_sort |
Grob, H. |
title |
Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
title_short |
Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
title_full |
Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
title_fullStr |
Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
title_full_unstemmed |
Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf |
title_sort |
reflection seismic indicators for submarine permafrost and gas hydrate distributions on the canadian arctic beaufort shelf |
publishDate |
2021 |
url |
https://oceanrep.geomar.de/id/eprint/53333/ |
long_lat |
ENVELOPE(-142.500,-142.500,70.000,70.000) |
geographic |
Arctic Beaufort Shelf |
geographic_facet |
Arctic Beaufort Shelf |
genre |
Arctic Arctic Beaufort Sea Climate change permafrost |
genre_facet |
Arctic Arctic Beaufort Sea Climate change permafrost |
op_relation |
Grob, H., Riedel, M. , Krastel, S. , Bustamante Restrepo, J., Duchesne, M. J., Fabien-Ouellet, G., Jin, Y. K. and Hong, J. K. (2021) Reflection seismic indicators for submarine permafrost and gas hydrate distributions on the Canadian Arctic Beaufort Shelf. [Poster] In: 81. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG). , 01.03.-05.03.2021, Kiel (online) . |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1766298452711440384 |