Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin
Abstract Mechanisms related to sub‐seabed fluid flow processes are complex and inadequately understood. Petrophysical properties, availability of gases, topography, stress directions, and various geological parameters determine the location and intensity of leakage which change over time. From tens...
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American Geophysical Union (AGU)
2023
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ftdoajarticles:oai:doaj.org/article:fc0f08d4aab242ac81932199f5b4a782 2023-11-12T04:27:03+01:00 Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin Sunny Singhroha Bettina Schramm Andreia Plaza‐Faverola Przemyslaw Domel Anke Dannowski Frances Cooke Stefan Bünz 2023-10-01T00:00:00Z https://doi.org/10.1029/2023EA003068 https://doaj.org/article/fc0f08d4aab242ac81932199f5b4a782 EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2023EA003068 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2023EA003068 https://doaj.org/article/fc0f08d4aab242ac81932199f5b4a782 Earth and Space Science, Vol 10, Iss 10, Pp n/a-n/a (2023) S‐wave analysis converted shear (PS) waves ocean‐bottom seismometer (OBS) fluid seepage anisotropy stress Astronomy QB1-991 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.1029/2023EA003068 2023-10-29T00:35:23Z Abstract Mechanisms related to sub‐seabed fluid flow processes are complex and inadequately understood. Petrophysical properties, availability of gases, topography, stress directions, and various geological parameters determine the location and intensity of leakage which change over time. From tens of seafloor pockmarks mapped along Vestnesa Ridge on the west‐Svalbard margin, only six show persistent present‐day seepage activity in sonar data. To investigate the causes of such restricted gas seepage, we conducted a study of anisotropy within the conduit feeding one of these active pockmarks (i.e., Lunde Pockmark). Lunde is ∼400–500 m in diameter, and atop a ∼300–400 m wide seismic chimney structure. We study seismic anisotropy using converted S‐wave data from 22 ocean‐bottom seismometers (OBSs) located in and around the pockmark. We investigate differences in symmetry plane directions in anisotropic media using null energy symmetries in transverse components. Subsurface stress distribution affects fault/fracture orientations and seismic anisotropy, and we use S‐wave and high‐resolution 3D seismic data to infer stress regimes in and around the active seep site and study the effect of stresses on seepage. We observe the occurrence of changes in dominant fault/fracture and horizontal stress orientations in and around Lunde Pockmark and conclude minimum (NE‐SW) and maximum (SE‐NW) horizontal stress directions. Our analysis indicates a potential correlation between hydrofractures and horizontal stresses, with up to a ∼32% higher probability of alignment of hydrofractures and faults perpendicular to the inferred minimum horizontal stress direction beneath the Lunde Pockmark area. Article in Journal/Newspaper Svalbard Svalbard margin Lunde Directory of Open Access Journals: DOAJ Articles Earth and Space Science 10 10 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
S‐wave analysis converted shear (PS) waves ocean‐bottom seismometer (OBS) fluid seepage anisotropy stress Astronomy QB1-991 Geology QE1-996.5 |
spellingShingle |
S‐wave analysis converted shear (PS) waves ocean‐bottom seismometer (OBS) fluid seepage anisotropy stress Astronomy QB1-991 Geology QE1-996.5 Sunny Singhroha Bettina Schramm Andreia Plaza‐Faverola Przemyslaw Domel Anke Dannowski Frances Cooke Stefan Bünz Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
topic_facet |
S‐wave analysis converted shear (PS) waves ocean‐bottom seismometer (OBS) fluid seepage anisotropy stress Astronomy QB1-991 Geology QE1-996.5 |
description |
Abstract Mechanisms related to sub‐seabed fluid flow processes are complex and inadequately understood. Petrophysical properties, availability of gases, topography, stress directions, and various geological parameters determine the location and intensity of leakage which change over time. From tens of seafloor pockmarks mapped along Vestnesa Ridge on the west‐Svalbard margin, only six show persistent present‐day seepage activity in sonar data. To investigate the causes of such restricted gas seepage, we conducted a study of anisotropy within the conduit feeding one of these active pockmarks (i.e., Lunde Pockmark). Lunde is ∼400–500 m in diameter, and atop a ∼300–400 m wide seismic chimney structure. We study seismic anisotropy using converted S‐wave data from 22 ocean‐bottom seismometers (OBSs) located in and around the pockmark. We investigate differences in symmetry plane directions in anisotropic media using null energy symmetries in transverse components. Subsurface stress distribution affects fault/fracture orientations and seismic anisotropy, and we use S‐wave and high‐resolution 3D seismic data to infer stress regimes in and around the active seep site and study the effect of stresses on seepage. We observe the occurrence of changes in dominant fault/fracture and horizontal stress orientations in and around Lunde Pockmark and conclude minimum (NE‐SW) and maximum (SE‐NW) horizontal stress directions. Our analysis indicates a potential correlation between hydrofractures and horizontal stresses, with up to a ∼32% higher probability of alignment of hydrofractures and faults perpendicular to the inferred minimum horizontal stress direction beneath the Lunde Pockmark area. |
format |
Article in Journal/Newspaper |
author |
Sunny Singhroha Bettina Schramm Andreia Plaza‐Faverola Przemyslaw Domel Anke Dannowski Frances Cooke Stefan Bünz |
author_facet |
Sunny Singhroha Bettina Schramm Andreia Plaza‐Faverola Przemyslaw Domel Anke Dannowski Frances Cooke Stefan Bünz |
author_sort |
Sunny Singhroha |
title |
Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
title_short |
Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
title_full |
Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
title_fullStr |
Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
title_full_unstemmed |
Stress Constraints From Shear‐Wave Analysis in Shallow Sediments at an Actively Seeping Pockmark on the W‐Svalbard Margin |
title_sort |
stress constraints from shear‐wave analysis in shallow sediments at an actively seeping pockmark on the w‐svalbard margin |
publisher |
American Geophysical Union (AGU) |
publishDate |
2023 |
url |
https://doi.org/10.1029/2023EA003068 https://doaj.org/article/fc0f08d4aab242ac81932199f5b4a782 |
genre |
Svalbard Svalbard margin Lunde |
genre_facet |
Svalbard Svalbard margin Lunde |
op_source |
Earth and Space Science, Vol 10, Iss 10, Pp n/a-n/a (2023) |
op_relation |
https://doi.org/10.1029/2023EA003068 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2023EA003068 https://doaj.org/article/fc0f08d4aab242ac81932199f5b4a782 |
op_doi |
https://doi.org/10.1029/2023EA003068 |
container_title |
Earth and Space Science |
container_volume |
10 |
container_issue |
10 |
_version_ |
1782340803404759040 |