Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin
Accepted for publication in Journal of Geophysical Research. Solid Earth. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted. Joint analysis of electrical resistivity and seismic velocity data is primarily used to detect the presence of gas hy...
Published in: | Journal of Geophysical Research: Solid Earth |
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2020
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Online Access: | https://hdl.handle.net/10037/17244 https://doi.org/10.1029/2019JB017949 |
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ftunivtroemsoe:oai:munin.uit.no:10037/17244 2023-05-15T14:26:01+02:00 Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin Singhroha, Sunny Bünz, Stefan Plaza-Faverola, Andreia Chand, Shyam 2020-01-24 https://hdl.handle.net/10037/17244 https://doi.org/10.1029/2019JB017949 eng eng American Geophysical Union (AGU) Journal of Geophysical Research (JGR): Solid Earth Norges forskningsråd: 287865 EC/H2020: 654462 Norges forskningsråd: 223259 Tromsø forskningsstiftelse: SEAMSTRESS info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ info:eu-repo/grantAgreement/RCN/FRINATEK/287865/Norway/Tectonic Stress Effects on Arctic Methane Seepage - SEAMSTRESS/SEAMSTRESS/ info:eu-repo/grantAgreement/EC/H2020/654462/EU/Strategies for Environmental Monitoring of Marine Carbon Capture and Storage/STEMM-CCS/ Singhroha S, Bünz S, Plaza-Faverola A, Chand S. Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin. Journal of Geophysical Research (JGR): Solid Earth. 2020 FRIDAID 1782365 doi:10.1029/2019JB017949 2169-9313 2169-9356 https://hdl.handle.net/10037/17244 openAccess ©2020 American Geophysical Union. All rights reserved. VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 Journal article Tidsskriftartikkel Peer reviewed acceptedVersion 2020 ftunivtroemsoe https://doi.org/10.1029/2019JB017949 2021-06-25T17:57:11Z Accepted for publication in Journal of Geophysical Research. Solid Earth. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted. Joint analysis of electrical resistivity and seismic velocity data is primarily used to detect the presence of gas hydrate‐filled faults and fractures. In this study, we present a novel approach to infer the occurrence of structurally‐controlled gas hydrate accumulations using azimuthal seismic velocity analysis. We perform this analysis using ocean‐bottom seismic (OBS) data at two sites on Vestnesa Ridge, W‐Svalbard Margin. Previous geophysical studies inferred the presence of gas hydrates at shallow depths (up to ~190‐195 m below the seafloor) in marine sediments of Vestnesa Ridge. We analyze azimuthal P‐wave seismic velocities in relation with steeply‐dipping near surface faults to study structural controls on gas hydrate distribution. This unique analysis documents directional changes in seismic velocities along and across faults. P‐wave velocities are elevated and reduced by ~0.06‐0.08 km/s in azimuths where the raypath plane lies along the fault plane in the gas hydrate stability zone (GHSZ) and below the base of the GHSZ, respectively. The resulting velocities can be explained with the presence of gas hydrate‐ and free gas‐filled faults above and below the base of the GHSZ, respectively. Moreover, the occurrence of elevated and reduced (>0.05 km/s) seismic velocities in groups of azimuths bounded by faults, suggests compartmentalization of gas hydrates and free gas by fault planes. Results from gas hydrate saturation modelling suggest that these observed changes in seismic velocities with azimuth can be due to gas hydrate saturated faults of thickness greater than 20 cm and considerably smaller than 300 cm. Article in Journal/Newspaper Arctic Svalbard Svalbard margin University of Tromsø: Munin Open Research Archive Svalbard Journal of Geophysical Research: Solid Earth 125 2 |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 |
spellingShingle |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 Singhroha, Sunny Bünz, Stefan Plaza-Faverola, Andreia Chand, Shyam Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
topic_facet |
VDP::Mathematics and natural science: 400::Geosciences: 450 VDP::Matematikk og Naturvitenskap: 400::Geofag: 450 |
description |
Accepted for publication in Journal of Geophysical Research. Solid Earth. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted. Joint analysis of electrical resistivity and seismic velocity data is primarily used to detect the presence of gas hydrate‐filled faults and fractures. In this study, we present a novel approach to infer the occurrence of structurally‐controlled gas hydrate accumulations using azimuthal seismic velocity analysis. We perform this analysis using ocean‐bottom seismic (OBS) data at two sites on Vestnesa Ridge, W‐Svalbard Margin. Previous geophysical studies inferred the presence of gas hydrates at shallow depths (up to ~190‐195 m below the seafloor) in marine sediments of Vestnesa Ridge. We analyze azimuthal P‐wave seismic velocities in relation with steeply‐dipping near surface faults to study structural controls on gas hydrate distribution. This unique analysis documents directional changes in seismic velocities along and across faults. P‐wave velocities are elevated and reduced by ~0.06‐0.08 km/s in azimuths where the raypath plane lies along the fault plane in the gas hydrate stability zone (GHSZ) and below the base of the GHSZ, respectively. The resulting velocities can be explained with the presence of gas hydrate‐ and free gas‐filled faults above and below the base of the GHSZ, respectively. Moreover, the occurrence of elevated and reduced (>0.05 km/s) seismic velocities in groups of azimuths bounded by faults, suggests compartmentalization of gas hydrates and free gas by fault planes. Results from gas hydrate saturation modelling suggest that these observed changes in seismic velocities with azimuth can be due to gas hydrate saturated faults of thickness greater than 20 cm and considerably smaller than 300 cm. |
format |
Article in Journal/Newspaper |
author |
Singhroha, Sunny Bünz, Stefan Plaza-Faverola, Andreia Chand, Shyam |
author_facet |
Singhroha, Sunny Bünz, Stefan Plaza-Faverola, Andreia Chand, Shyam |
author_sort |
Singhroha, Sunny |
title |
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
title_short |
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
title_full |
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
title_fullStr |
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
title_full_unstemmed |
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin |
title_sort |
detectionof gas hydrates infaults using azimuthal seismic velocity analysis,vestnesa ridge, w-svalbard margin |
publisher |
American Geophysical Union (AGU) |
publishDate |
2020 |
url |
https://hdl.handle.net/10037/17244 https://doi.org/10.1029/2019JB017949 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Arctic Svalbard Svalbard margin |
genre_facet |
Arctic Svalbard Svalbard margin |
op_relation |
Journal of Geophysical Research (JGR): Solid Earth Norges forskningsråd: 287865 EC/H2020: 654462 Norges forskningsråd: 223259 Tromsø forskningsstiftelse: SEAMSTRESS info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ info:eu-repo/grantAgreement/RCN/FRINATEK/287865/Norway/Tectonic Stress Effects on Arctic Methane Seepage - SEAMSTRESS/SEAMSTRESS/ info:eu-repo/grantAgreement/EC/H2020/654462/EU/Strategies for Environmental Monitoring of Marine Carbon Capture and Storage/STEMM-CCS/ Singhroha S, Bünz S, Plaza-Faverola A, Chand S. Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin. Journal of Geophysical Research (JGR): Solid Earth. 2020 FRIDAID 1782365 doi:10.1029/2019JB017949 2169-9313 2169-9356 https://hdl.handle.net/10037/17244 |
op_rights |
openAccess ©2020 American Geophysical Union. All rights reserved. |
op_doi |
https://doi.org/10.1029/2019JB017949 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
125 |
container_issue |
2 |
_version_ |
1766298504475443200 |