Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis
Large earthquakes near active volcanoes, that exhibit non-double-couple source properties are usually interpreted as result the of either magma intrusion or geometrical complexity along the fault plane. Such an earthquake occurred in 1996 September 29 at Bárdarbunga volcano in central Iceland, to be...
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fthighwire:oai:open-archive.highwire.org:gji:154/1/134 2023-05-15T16:21:45+02:00 Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis Konstantinou, Konstantinos I. Kao, Honn Lin, Cheng-Horng Liang, Wen-Tzong 2003-07-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/154/1/134 https://doi.org/10.1046/j.1365-246X.2003.01932.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/154/1/134 http://dx.doi.org/10.1046/j.1365-246X.2003.01932.x Copyright (C) 2003, Oxford University Press Articles TEXT 2003 fthighwire https://doi.org/10.1046/j.1365-246X.2003.01932.x 2013-05-27T00:04:57Z Large earthquakes near active volcanoes, that exhibit non-double-couple source properties are usually interpreted as result the of either magma intrusion or geometrical complexity along the fault plane. Such an earthquake occurred in 1996 September 29 at Bárdarbunga volcano in central Iceland, to be followed 2 days later by a major volcanic eruption at the area between Bárdarbunga and the nearby Grimsvötn volcano. Both of these active volcanic centres lie underneath the Vatnajökull glacier, a permanent ice cap that covers a large area of central Iceland. This event was recorded by a temporary network (HOTSPOT) that consisted of 30 broad-band three-component seismometers covering most of Iceland. The waveforms of this event at all stations show an emergent, low-amplitude, high-frequency onset that is superposed on a longer-period signal. The corresponding amplitude spectra show a low-frequency content (<1 Hz) and prominent peaks around the corner frequency (∼0.25 Hz) and higher frequencies. These regional waveforms were inverted in order to obtain the best-fitting deviatoric and full moment tensor using a linear, time-domain inversion method. The results for the deviatoric moment tensor indicate a large (∼60 per cent) compensated linear vector dipole (CLVD) component, a hypocentral depth of 3.5 km, a moment magnitude of 5.4 and a best double-couple solution showing thrust motion in good agreement with the previously published Harvard CMT solution. The results for the full moment tensor on the other hand, indicate an implosive isotropic component of 8.5 per cent, a reduced CLVD component of 47.2 per cent and a best double-couple solution showing normal faulting. However, a statistical F-test revealed that the full moment tensor does not fit the data significantly better than the deviatoric at a confidence level of not more than 76 per cent. All of these results were found not to change substantially when a different source time function was used or when the data were weighted according to their distance from ... Text glacier Ice cap Iceland Vatnajökull HighWire Press (Stanford University) Vatnajökull ENVELOPE(-16.823,-16.823,64.420,64.420) Bardarbunga ENVELOPE(-17.528,-17.528,64.635,64.635) Geophysical Journal International 154 1 134 145 |
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Articles Konstantinou, Konstantinos I. Kao, Honn Lin, Cheng-Horng Liang, Wen-Tzong Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
topic_facet |
Articles |
description |
Large earthquakes near active volcanoes, that exhibit non-double-couple source properties are usually interpreted as result the of either magma intrusion or geometrical complexity along the fault plane. Such an earthquake occurred in 1996 September 29 at Bárdarbunga volcano in central Iceland, to be followed 2 days later by a major volcanic eruption at the area between Bárdarbunga and the nearby Grimsvötn volcano. Both of these active volcanic centres lie underneath the Vatnajökull glacier, a permanent ice cap that covers a large area of central Iceland. This event was recorded by a temporary network (HOTSPOT) that consisted of 30 broad-band three-component seismometers covering most of Iceland. The waveforms of this event at all stations show an emergent, low-amplitude, high-frequency onset that is superposed on a longer-period signal. The corresponding amplitude spectra show a low-frequency content (<1 Hz) and prominent peaks around the corner frequency (∼0.25 Hz) and higher frequencies. These regional waveforms were inverted in order to obtain the best-fitting deviatoric and full moment tensor using a linear, time-domain inversion method. The results for the deviatoric moment tensor indicate a large (∼60 per cent) compensated linear vector dipole (CLVD) component, a hypocentral depth of 3.5 km, a moment magnitude of 5.4 and a best double-couple solution showing thrust motion in good agreement with the previously published Harvard CMT solution. The results for the full moment tensor on the other hand, indicate an implosive isotropic component of 8.5 per cent, a reduced CLVD component of 47.2 per cent and a best double-couple solution showing normal faulting. However, a statistical F-test revealed that the full moment tensor does not fit the data significantly better than the deviatoric at a confidence level of not more than 76 per cent. All of these results were found not to change substantially when a different source time function was used or when the data were weighted according to their distance from ... |
format |
Text |
author |
Konstantinou, Konstantinos I. Kao, Honn Lin, Cheng-Horng Liang, Wen-Tzong |
author_facet |
Konstantinou, Konstantinos I. Kao, Honn Lin, Cheng-Horng Liang, Wen-Tzong |
author_sort |
Konstantinou, Konstantinos I. |
title |
Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
title_short |
Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
title_full |
Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
title_fullStr |
Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
title_full_unstemmed |
Analysis of broad-band regional waveforms of the 1996 September 29 earthquake at Bardarbunga volcano, central Iceland: investigation of the magma injection hypothesis |
title_sort |
analysis of broad-band regional waveforms of the 1996 september 29 earthquake at bardarbunga volcano, central iceland: investigation of the magma injection hypothesis |
publisher |
Oxford University Press |
publishDate |
2003 |
url |
http://gji.oxfordjournals.org/cgi/content/short/154/1/134 https://doi.org/10.1046/j.1365-246X.2003.01932.x |
long_lat |
ENVELOPE(-16.823,-16.823,64.420,64.420) ENVELOPE(-17.528,-17.528,64.635,64.635) |
geographic |
Vatnajökull Bardarbunga |
geographic_facet |
Vatnajökull Bardarbunga |
genre |
glacier Ice cap Iceland Vatnajökull |
genre_facet |
glacier Ice cap Iceland Vatnajökull |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/154/1/134 http://dx.doi.org/10.1046/j.1365-246X.2003.01932.x |
op_rights |
Copyright (C) 2003, Oxford University Press |
op_doi |
https://doi.org/10.1046/j.1365-246X.2003.01932.x |
container_title |
Geophysical Journal International |
container_volume |
154 |
container_issue |
1 |
container_start_page |
134 |
op_container_end_page |
145 |
_version_ |
1766009732008509440 |