Teleseismic earthquake wavefields observed on the Ross Ice Shelf
Observations of teleseismic earthquakes using broadband seismometers on the Ross Ice Shelf (RIS) must contend with environmental and structural processes that do not exist for land-sited seismometers. Important considerations are: (1) a broadband, multi-mode ambient wavefield excited by ocean gravit...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2021-02-01
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| Series: | Journal of Glaciology |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143020000830/type/journal_article |
| _version_ | 1811155828155088896 |
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| author | Michael G. Baker Richard C. Aster Douglas A. Wiens Andrew Nyblade Peter D. Bromirski Peter Gerstoft Ralph A. Stephen |
| author_facet | Michael G. Baker Richard C. Aster Douglas A. Wiens Andrew Nyblade Peter D. Bromirski Peter Gerstoft Ralph A. Stephen |
| author_sort | Michael G. Baker |
| collection | DOAJ |
| description | Observations of teleseismic earthquakes using broadband seismometers on the Ross Ice Shelf (RIS) must contend with environmental and structural processes that do not exist for land-sited seismometers. Important considerations are: (1) a broadband, multi-mode ambient wavefield excited by ocean gravity wave interactions with the ice shelf; (2) body wave reverberations produced by seismic impedance contrasts at the ice/water and water/seafloor interfaces and (3) decoupling of the solid Earth horizontal wavefield by the sub-shelf water column. We analyze seasonal and geographic variations in signal-to-noise ratios for teleseismic P-wave (0.5–2.0 s), S-wave (10–15 s) and surface wave (13–25 s) arrivals relative to the RIS noise field. We use ice and water layer reverberations generated by teleseismic P-waves to accurately estimate the sub-station thicknesses of these layers. We present observations consistent with the theoretically predicted transition of the water column from compressible to incompressible mechanics, relevant for vertically incident solid Earth waves with periods longer than 3 s. Finally, we observe symmetric-mode Lamb waves generated by teleseismic S-waves incident on the grounding zones. Despite their complexity, we conclude that teleseismic coda can be utilized for passive imaging of sub-shelf Earth structure, although longer deployments relative to conventional land-sited seismometers will be necessary to acquire adequate data. |
| first_indexed | 2024-04-10T04:40:09Z |
| format | Article |
| id | doaj.art-dc4cbbeaba5f45968e61add8f780e6b2 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:40:09Z |
| publishDate | 2021-02-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-dc4cbbeaba5f45968e61add8f780e6b22023-03-09T12:41:02ZengCambridge University PressJournal of Glaciology0022-14301727-56522021-02-0167587410.1017/jog.2020.83Teleseismic earthquake wavefields observed on the Ross Ice ShelfMichael G. Baker0https://orcid.org/0000-0002-4580-6820Richard C. Aster1Douglas A. Wiens2Andrew Nyblade3Peter D. Bromirski4Peter Gerstoft5Ralph A. Stephen6Department of Geosciences, Colorado State University, Fort Collins, CO, USADepartment of Geosciences, Colorado State University, Fort Collins, CO, USADepartment of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USADepartment of Geosciences, Pennsylvania State University, University Park, PA, USAScripps Institute of Oceanography, University of California, San Diego, CA, USAScripps Institute of Oceanography, University of California, San Diego, CA, USAWoods Hole Oceanographic Institution, Woods Hole, MA, USAObservations of teleseismic earthquakes using broadband seismometers on the Ross Ice Shelf (RIS) must contend with environmental and structural processes that do not exist for land-sited seismometers. Important considerations are: (1) a broadband, multi-mode ambient wavefield excited by ocean gravity wave interactions with the ice shelf; (2) body wave reverberations produced by seismic impedance contrasts at the ice/water and water/seafloor interfaces and (3) decoupling of the solid Earth horizontal wavefield by the sub-shelf water column. We analyze seasonal and geographic variations in signal-to-noise ratios for teleseismic P-wave (0.5–2.0 s), S-wave (10–15 s) and surface wave (13–25 s) arrivals relative to the RIS noise field. We use ice and water layer reverberations generated by teleseismic P-waves to accurately estimate the sub-station thicknesses of these layers. We present observations consistent with the theoretically predicted transition of the water column from compressible to incompressible mechanics, relevant for vertically incident solid Earth waves with periods longer than 3 s. Finally, we observe symmetric-mode Lamb waves generated by teleseismic S-waves incident on the grounding zones. Despite their complexity, we conclude that teleseismic coda can be utilized for passive imaging of sub-shelf Earth structure, although longer deployments relative to conventional land-sited seismometers will be necessary to acquire adequate data.https://www.cambridge.org/core/product/identifier/S0022143020000830/type/journal_articleGlacier geophysicsice shelvesseismology |
| spellingShingle | Michael G. Baker Richard C. Aster Douglas A. Wiens Andrew Nyblade Peter D. Bromirski Peter Gerstoft Ralph A. Stephen Teleseismic earthquake wavefields observed on the Ross Ice Shelf Journal of Glaciology Glacier geophysics ice shelves seismology |
| title | Teleseismic earthquake wavefields observed on the Ross Ice Shelf |
| title_full | Teleseismic earthquake wavefields observed on the Ross Ice Shelf |
| title_fullStr | Teleseismic earthquake wavefields observed on the Ross Ice Shelf |
| title_full_unstemmed | Teleseismic earthquake wavefields observed on the Ross Ice Shelf |
| title_short | Teleseismic earthquake wavefields observed on the Ross Ice Shelf |
| title_sort | teleseismic earthquake wavefields observed on the ross ice shelf |
| topic | Glacier geophysics ice shelves seismology |
| url | https://www.cambridge.org/core/product/identifier/S0022143020000830/type/journal_article |
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