Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes
We recorded high-frequency (> 10 Hz) harmonic tremor with spectral gliding at Hekla volcano in Iceland. Particle motion plots indicated a shallow tremor source. We observed up to two overtones beneath our Nyquist frequency of 50 Hz and could resolve a source of closely spaced pulses of very short...
Published in: | Journal of Volcanology and Geothermal Research |
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Online Access: | https://zenodo.org/record/53146 https://doi.org/10.1016/j.jvolgeores.2015.08.002 |
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ftzenodo:oai:zenodo.org:53146 2023-06-06T11:54:37+02:00 Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akelie, Eggert Vogfjörd, Kristín S. 2015-08-12 https://zenodo.org/record/53146 https://doi.org/10.1016/j.jvolgeores.2015.08.002 unknown info:eu-repo/grantAgreement/EC/FP7/308377/ https://zenodo.org/communities/ecfunded https://zenodo.org/record/53146 https://doi.org/10.1016/j.jvolgeores.2015.08.002 oai:zenodo.org:53146 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode Journal of Volcanology and Geothermal Research 304 108-117 (2015) Frequency gliding Doppler shift Harmonic tremor Helicopter Volcano info:eu-repo/semantics/article publication-article 2015 ftzenodo https://doi.org/10.1016/j.jvolgeores.2015.08.002 2023-04-13T23:39:30Z We recorded high-frequency (> 10 Hz) harmonic tremor with spectral gliding at Hekla volcano in Iceland. Particle motion plots indicated a shallow tremor source. We observed up to two overtones beneath our Nyquist frequency of 50 Hz and could resolve a source of closely spaced pulses of very short duration (0.03 - 0.1 s) on zoomed seismograms. Volcanic tremor with fundamental frequencies above 5 Hz, frequency gliding and/or repetitive sources similar to our observations were observed on different volcanoes around the world. However, this frequency content, duration and occurrence of volcano-related tremor was not observed in the last 35 years of seismic observations at Hekla. Detailed analysis reveals that this tremor was related to helicopters passing the volcano. This study relates the GPS track of a helicopter with seismic recordings of the helicopter at various distances. We show the effect the distance, number of rotor blades and velocity of the helicopter has on the observed up and down glidings at up to 40 km distance. We highlight similarities and differences between volcano-related and helicopter tremor in order to help avoid misinterpretations. Article in Journal/Newspaper Hekla Iceland Zenodo Journal of Volcanology and Geothermal Research 304 108 117 |
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topic |
Frequency gliding Doppler shift Harmonic tremor Helicopter Volcano |
spellingShingle |
Frequency gliding Doppler shift Harmonic tremor Helicopter Volcano Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akelie, Eggert Vogfjörd, Kristín S. Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
topic_facet |
Frequency gliding Doppler shift Harmonic tremor Helicopter Volcano |
description |
We recorded high-frequency (> 10 Hz) harmonic tremor with spectral gliding at Hekla volcano in Iceland. Particle motion plots indicated a shallow tremor source. We observed up to two overtones beneath our Nyquist frequency of 50 Hz and could resolve a source of closely spaced pulses of very short duration (0.03 - 0.1 s) on zoomed seismograms. Volcanic tremor with fundamental frequencies above 5 Hz, frequency gliding and/or repetitive sources similar to our observations were observed on different volcanoes around the world. However, this frequency content, duration and occurrence of volcano-related tremor was not observed in the last 35 years of seismic observations at Hekla. Detailed analysis reveals that this tremor was related to helicopters passing the volcano. This study relates the GPS track of a helicopter with seismic recordings of the helicopter at various distances. We show the effect the distance, number of rotor blades and velocity of the helicopter has on the observed up and down glidings at up to 40 km distance. We highlight similarities and differences between volcano-related and helicopter tremor in order to help avoid misinterpretations. |
format |
Article in Journal/Newspaper |
author |
Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akelie, Eggert Vogfjörd, Kristín S. |
author_facet |
Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akelie, Eggert Vogfjörd, Kristín S. |
author_sort |
Eibl, Eva P. S. |
title |
Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
title_short |
Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
title_full |
Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
title_fullStr |
Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
title_full_unstemmed |
Helicopter vs. Volcanic Tremor: Characteristic Features of Seismic Harmonic Tremor on Volcanoes |
title_sort |
helicopter vs. volcanic tremor: characteristic features of seismic harmonic tremor on volcanoes |
publishDate |
2015 |
url |
https://zenodo.org/record/53146 https://doi.org/10.1016/j.jvolgeores.2015.08.002 |
genre |
Hekla Iceland |
genre_facet |
Hekla Iceland |
op_source |
Journal of Volcanology and Geothermal Research 304 108-117 (2015) |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/308377/ https://zenodo.org/communities/ecfunded https://zenodo.org/record/53146 https://doi.org/10.1016/j.jvolgeores.2015.08.002 oai:zenodo.org:53146 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/legalcode |
op_doi |
https://doi.org/10.1016/j.jvolgeores.2015.08.002 |
container_title |
Journal of Volcanology and Geothermal Research |
container_volume |
304 |
container_start_page |
108 |
op_container_end_page |
117 |
_version_ |
1767961133411467264 |