Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica
2020 Summer. Includes bibliographical references. Repeating swarms of local icequakes were recorded by broadband seismograpghs deployed near the grounding line of the Ross Ice Shelf, Antarctica from late 2014 to early 2017. Swarms commonly persist for over six hours and contain thousands of events....
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ftcolostateunidc:oai:mountainscholar.org:10217/212036 2023-06-11T04:04:53+02:00 Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica Cole, Hank M. Aster, Richard C. McGrath, Daniel Cheney, Margaret Benz, Harley 2020-09-07T10:08:40Z born digital masters theses application/pdf https://hdl.handle.net/10217/212036 English eng eng Colorado State University. Libraries 2020- CSU Theses and Dissertations Cole_colostate_0053N_16180.pdf https://hdl.handle.net/10217/212036 Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. grounding line icequakes tides ice shelf seismology Antarctica Text 2020 ftcolostateunidc 2023-05-04T17:38:00Z 2020 Summer. Includes bibliographical references. Repeating swarms of local icequakes were recorded by broadband seismograpghs deployed near the grounding line of the Ross Ice Shelf, Antarctica from late 2014 to early 2017. Swarms commonly persist for over six hours and contain thousands of events. Most swarms are induced or enhanced by tidal forcing. The number of events and event amplitudes in a swarm is most correlated with the modeled tide range. Some swarms only occur during cold periods of the austral winter. Icequakes are cataloged using a cross-correlation detector after building a template library from clustered STA/LTA picks and epicenters are estimated for high quality events. Events can be classified into four broad categories. The first event type is the most common (>95% of events) and occurs in diurnal swarms at all times of year. This type of event is interpreted to be sourced by propagation of near surface crevasses due to enhanced tensile stress from downward flexure of the ice shelf during falling tide. The second type of event has similar waveforms but occurs at the crest of large spring tides and appears to have an englacial or basal source. The third type of event is likely sourced from within the firn, possibly related to densification. It is also observed at stations in the ice shelf interior, but appears enhanced by tides at stations near the grounding line. The fourth type of event is only observed at a station on the Steershead Ice Rise. These are sweeping harmonic tremors lasting up to 8 s that start at low frequency and then tail upwards into an impulse like signal. This work characterizes these icequake types and their correlation to tidal and environmental forcing. It also details a single station event location scheme that is to used to further interpret events by finding their back azimuth with a polarization analysis and estimate their source-receiver distance with two methods. These observations provide insight into the deformation and brittle fracture at the grounded ... Text Antarc* Antarctica Ice Shelf Ross Ice Shelf Digital Collections of Colorado (Colorado State University) Austral Ross Ice Shelf |
institution |
Open Polar |
collection |
Digital Collections of Colorado (Colorado State University) |
op_collection_id |
ftcolostateunidc |
language |
English |
topic |
grounding line icequakes tides ice shelf seismology Antarctica |
spellingShingle |
grounding line icequakes tides ice shelf seismology Antarctica Cole, Hank M. Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
topic_facet |
grounding line icequakes tides ice shelf seismology Antarctica |
description |
2020 Summer. Includes bibliographical references. Repeating swarms of local icequakes were recorded by broadband seismograpghs deployed near the grounding line of the Ross Ice Shelf, Antarctica from late 2014 to early 2017. Swarms commonly persist for over six hours and contain thousands of events. Most swarms are induced or enhanced by tidal forcing. The number of events and event amplitudes in a swarm is most correlated with the modeled tide range. Some swarms only occur during cold periods of the austral winter. Icequakes are cataloged using a cross-correlation detector after building a template library from clustered STA/LTA picks and epicenters are estimated for high quality events. Events can be classified into four broad categories. The first event type is the most common (>95% of events) and occurs in diurnal swarms at all times of year. This type of event is interpreted to be sourced by propagation of near surface crevasses due to enhanced tensile stress from downward flexure of the ice shelf during falling tide. The second type of event has similar waveforms but occurs at the crest of large spring tides and appears to have an englacial or basal source. The third type of event is likely sourced from within the firn, possibly related to densification. It is also observed at stations in the ice shelf interior, but appears enhanced by tides at stations near the grounding line. The fourth type of event is only observed at a station on the Steershead Ice Rise. These are sweeping harmonic tremors lasting up to 8 s that start at low frequency and then tail upwards into an impulse like signal. This work characterizes these icequake types and their correlation to tidal and environmental forcing. It also details a single station event location scheme that is to used to further interpret events by finding their back azimuth with a polarization analysis and estimate their source-receiver distance with two methods. These observations provide insight into the deformation and brittle fracture at the grounded ... |
author2 |
Aster, Richard C. McGrath, Daniel Cheney, Margaret Benz, Harley |
format |
Text |
author |
Cole, Hank M. |
author_facet |
Cole, Hank M. |
author_sort |
Cole, Hank M. |
title |
Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
title_short |
Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
title_full |
Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
title_fullStr |
Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
title_full_unstemmed |
Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica |
title_sort |
tidally induced seismicity at the grounded margins of the ross ice shelf, antarctica |
publisher |
Colorado State University. Libraries |
publishDate |
2020 |
url |
https://hdl.handle.net/10217/212036 |
geographic |
Austral Ross Ice Shelf |
geographic_facet |
Austral Ross Ice Shelf |
genre |
Antarc* Antarctica Ice Shelf Ross Ice Shelf |
genre_facet |
Antarc* Antarctica Ice Shelf Ross Ice Shelf |
op_relation |
2020- CSU Theses and Dissertations Cole_colostate_0053N_16180.pdf https://hdl.handle.net/10217/212036 |
op_rights |
Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. |
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1768391559361855488 |