Seismic acquisition and analysis in a changing Arctic
In the Arctic, temperatures are regularly low enough that water exists in its frozen state, either in the form of ice, snow, or frozen ground. The effective elastic properties of a material depend on the elastic properties of the individual constituents and their geometrical distribution. Since soli...
Main Author: | |
---|---|
Other Authors: | |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
The University of Bergen
2020
|
Subjects: | |
Online Access: | https://hdl.handle.net/11250/2711278 |
id |
ftunivbergen:oai:bora.uib.no:11250/2711278 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
description |
In the Arctic, temperatures are regularly low enough that water exists in its frozen state, either in the form of ice, snow, or frozen ground. The effective elastic properties of a material depend on the elastic properties of the individual constituents and their geometrical distribution. Since solid ice is stiffer and more rigid than liquid water, effective elastic properties (bulk and shear modulus) increase with increasing degree of freezing; however, the properties strongly depend on the pore ice morphology, so the relationship is not linear. Seismic waves propagate with velocities that depend on the effective elastic properties of the medium they travel in. Hence, seismic waves travel faster in frozen materials than in similar unfrozen materials, and the velocity depth profile in near-surface Arctic rocks is often irregular. Due to this, seismic records from Arctic environments often show dominating and highly dispersive surface waves. The Arctic surface is today warming at the most rapid pace on earth, but knowledge about the following consequences on the physical properties of the subsurface is scarce. How surface temperature is transmitted to depth and how this affects the mechanical properties of the subsurface is uncertain, in particular for areas with saline pore water. Since the stability of near-surface sediments is largely governed by their mechanical properties, understanding how these properties vary in a temporally changing Arctic is vital. The overall objective of this study is to investigate how to safely acquire seismic data for mapping and monitoring of the near-surface sediments in a changing Arctic climate. To address this, we use seismic data acquired on Svalbard in the Norwegian Arctic. We first investigate whether seismic data can be acquired without affecting the vulnerable Arctic animal life (Paper 1), and then investigate how both long- and short-term surface temperature variations affect effective elastic properties (Paper 2) and the seismic wavefield (Paper 3 and Paper 4). We find ... |
author2 |
orcid:0000-0002-0878-0473 |
format |
Doctoral or Postdoctoral Thesis |
author |
Stemland, Helene Meling |
spellingShingle |
Stemland, Helene Meling Seismic acquisition and analysis in a changing Arctic |
author_facet |
Stemland, Helene Meling |
author_sort |
Stemland, Helene Meling |
title |
Seismic acquisition and analysis in a changing Arctic |
title_short |
Seismic acquisition and analysis in a changing Arctic |
title_full |
Seismic acquisition and analysis in a changing Arctic |
title_fullStr |
Seismic acquisition and analysis in a changing Arctic |
title_full_unstemmed |
Seismic acquisition and analysis in a changing Arctic |
title_sort |
seismic acquisition and analysis in a changing arctic |
publisher |
The University of Bergen |
publishDate |
2020 |
url |
https://hdl.handle.net/11250/2711278 |
geographic |
Arctic Svalbard |
geographic_facet |
Arctic Svalbard |
genre |
Arctic Arctic Svalbard The Cryosphere |
genre_facet |
Arctic Arctic Svalbard The Cryosphere |
op_relation |
Paper 1: Stemland, H. M., Johansen, T. A., Ruud, B. O., & Aniceto, A. S. (2019). Measured sound levels in ice-covered shallow water caused by seismic shooting on top of and below floating ice, reviewed for possible impacts on true seals. First Break, 37(1), 35-42. The article is not available in BORA due to publisher restrictions. The published version is available at: https://doi.org/10.3997/1365-2397.2018010 Paper 2: Stemland, H. M., Johansen, T. A., Ruud, B. O., & Mavko, G. (2020). Elastic properties as indicators of heat flux into cold near-surface Arctic sediments. Geophysics, 85(5), 1SO-Z24. The accepted version is available in the thesis file. The published version is available at: https://doi.org/10.1190/geo2019-0662.1 Paper 3: Stemland, H. M., Johansen, T. A., & Ruud, B. O. (2020). Potential Use of Time-Lapse Surface Seismics for Monitoring Thawing of the Terrestrial Arctic. Applied Sciences, 10(5), 1875. The article is available in the thesis file. The article is also available at: https://doi.org/10.3390/app10051875 Paper 4: Romeyn, R., Hanssen, A., Ruud, B. O., Stemland, H. M., & Johansen, T. A. (2020). Passive seismic recording of cryoseisms in Adventdalen, Svalbard. The Cryosphere. The submitted version is available in the thesis file. The article is also available at: https://doi.org/10.5194/tc-2020-141 container/d3/ad/45/27/d3ad4527-223a-4230-be01-eecba775b78b urn:isbn:9788230854631 urn:isbn:9788230867419 https://hdl.handle.net/11250/2711278 |
op_rights |
Attribution-NonCommercial-NoDerivs (CC BY-NC-ND). This item's rights statement or license does not apply to the included articles in the thesis. https://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright the Author. |
_version_ |
1766302184034533376 |
spelling |
ftunivbergen:oai:bora.uib.no:11250/2711278 2023-05-15T14:28:03+02:00 Seismic acquisition and analysis in a changing Arctic Stemland, Helene Meling orcid:0000-0002-0878-0473 2020-11-16T11:22:08.422Z application/pdf https://hdl.handle.net/11250/2711278 eng eng The University of Bergen Paper 1: Stemland, H. M., Johansen, T. A., Ruud, B. O., & Aniceto, A. S. (2019). Measured sound levels in ice-covered shallow water caused by seismic shooting on top of and below floating ice, reviewed for possible impacts on true seals. First Break, 37(1), 35-42. The article is not available in BORA due to publisher restrictions. The published version is available at: https://doi.org/10.3997/1365-2397.2018010 Paper 2: Stemland, H. M., Johansen, T. A., Ruud, B. O., & Mavko, G. (2020). Elastic properties as indicators of heat flux into cold near-surface Arctic sediments. Geophysics, 85(5), 1SO-Z24. The accepted version is available in the thesis file. The published version is available at: https://doi.org/10.1190/geo2019-0662.1 Paper 3: Stemland, H. M., Johansen, T. A., & Ruud, B. O. (2020). Potential Use of Time-Lapse Surface Seismics for Monitoring Thawing of the Terrestrial Arctic. Applied Sciences, 10(5), 1875. The article is available in the thesis file. The article is also available at: https://doi.org/10.3390/app10051875 Paper 4: Romeyn, R., Hanssen, A., Ruud, B. O., Stemland, H. M., & Johansen, T. A. (2020). Passive seismic recording of cryoseisms in Adventdalen, Svalbard. The Cryosphere. The submitted version is available in the thesis file. The article is also available at: https://doi.org/10.5194/tc-2020-141 container/d3/ad/45/27/d3ad4527-223a-4230-be01-eecba775b78b urn:isbn:9788230854631 urn:isbn:9788230867419 https://hdl.handle.net/11250/2711278 Attribution-NonCommercial-NoDerivs (CC BY-NC-ND). This item's rights statement or license does not apply to the included articles in the thesis. https://creativecommons.org/licenses/by-nc-nd/4.0/ Copyright the Author. Doctoral thesis 2020 ftunivbergen 2023-03-14T17:44:36Z In the Arctic, temperatures are regularly low enough that water exists in its frozen state, either in the form of ice, snow, or frozen ground. The effective elastic properties of a material depend on the elastic properties of the individual constituents and their geometrical distribution. Since solid ice is stiffer and more rigid than liquid water, effective elastic properties (bulk and shear modulus) increase with increasing degree of freezing; however, the properties strongly depend on the pore ice morphology, so the relationship is not linear. Seismic waves propagate with velocities that depend on the effective elastic properties of the medium they travel in. Hence, seismic waves travel faster in frozen materials than in similar unfrozen materials, and the velocity depth profile in near-surface Arctic rocks is often irregular. Due to this, seismic records from Arctic environments often show dominating and highly dispersive surface waves. The Arctic surface is today warming at the most rapid pace on earth, but knowledge about the following consequences on the physical properties of the subsurface is scarce. How surface temperature is transmitted to depth and how this affects the mechanical properties of the subsurface is uncertain, in particular for areas with saline pore water. Since the stability of near-surface sediments is largely governed by their mechanical properties, understanding how these properties vary in a temporally changing Arctic is vital. The overall objective of this study is to investigate how to safely acquire seismic data for mapping and monitoring of the near-surface sediments in a changing Arctic climate. To address this, we use seismic data acquired on Svalbard in the Norwegian Arctic. We first investigate whether seismic data can be acquired without affecting the vulnerable Arctic animal life (Paper 1), and then investigate how both long- and short-term surface temperature variations affect effective elastic properties (Paper 2) and the seismic wavefield (Paper 3 and Paper 4). We find ... Doctoral or Postdoctoral Thesis Arctic Arctic Svalbard The Cryosphere University of Bergen: Bergen Open Research Archive (BORA-UiB) Arctic Svalbard |