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...
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ftdublininstadvs:oai:dair.dias.ie:381 2023-05-15T16:34:02+02:00 Helicopter vs. volcanic tremor: Characteristic features of seismic harmonic tremor on volcanoes Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akerlie, Eggert Vogfjörd, Kristin S. 2015 text https://dair.dias.ie/id/eprint/381/ https://dair.dias.ie/id/eprint/381/1/Eibl_et_al_JVGR_2015.pdf https://www.sciencedirect.com/science/article/pii/S0377027315002516 en eng https://dair.dias.ie/id/eprint/381/1/Eibl_et_al_JVGR_2015.pdf Eibl, Eva P. S. and Lokmer, Ivan and Bean, Christopher J. and Akerlie, Eggert and Vogfjörd, Kristin S. (2015) Helicopter vs. volcanic tremor: Characteristic features of seismic harmonic tremor on volcanoes. Journal of Volcanology and Geothermal Research, 304. pp. 108-117. Article PeerReviewed 2015 ftdublininstadvs 2022-12-22T23:59:48Z 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 Dublin Institute for Advanced Studies: DIAS Institutional Repository |
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Dublin Institute for Advanced Studies: DIAS Institutional Repository |
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English |
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. Akerlie, Eggert Vogfjörd, Kristin S. |
spellingShingle |
Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akerlie, Eggert Vogfjörd, Kristin S. Helicopter vs. volcanic tremor: Characteristic features of seismic harmonic tremor on volcanoes |
author_facet |
Eibl, Eva P. S. Lokmer, Ivan Bean, Christopher J. Akerlie, Eggert Vogfjörd, Kristin 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://dair.dias.ie/id/eprint/381/ https://dair.dias.ie/id/eprint/381/1/Eibl_et_al_JVGR_2015.pdf https://www.sciencedirect.com/science/article/pii/S0377027315002516 |
genre |
Hekla Iceland |
genre_facet |
Hekla Iceland |
op_relation |
https://dair.dias.ie/id/eprint/381/1/Eibl_et_al_JVGR_2015.pdf Eibl, Eva P. S. and Lokmer, Ivan and Bean, Christopher J. and Akerlie, Eggert and Vogfjörd, Kristin S. (2015) Helicopter vs. volcanic tremor: Characteristic features of seismic harmonic tremor on volcanoes. Journal of Volcanology and Geothermal Research, 304. pp. 108-117. |
_version_ |
1766023779047178240 |