Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland)
Relative relocation methods are commonly used to precisely relocate earthquake clusters consisting of similar waveforms. Repeating waveforms are often recorded at volcanoes, where, however, the crust structure is expected to contain strong heterogeneities and therefore the 1D velocity model assumpti...
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ftdatacite:10.48550/arxiv.1603.09253 2023-05-15T16:21:47+02:00 Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) Sgattoni, Giulia Guðmundsson, Ólafur Einarsson, Páll Lucchi, Federico 2016 https://dx.doi.org/10.48550/arxiv.1603.09253 https://arxiv.org/abs/1603.09253 unknown arXiv https://dx.doi.org/10.1093/gji/ggw331 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Geophysics physics.geo-ph FOS Physical sciences article-journal Article ScholarlyArticle Text 2016 ftdatacite https://doi.org/10.48550/arxiv.1603.09253 https://doi.org/10.1093/gji/ggw331 2022-04-01T11:42:30Z Relative relocation methods are commonly used to precisely relocate earthquake clusters consisting of similar waveforms. Repeating waveforms are often recorded at volcanoes, where, however, the crust structure is expected to contain strong heterogeneities and therefore the 1D velocity model assumption that is made in most location strategies is not likely to describe reality. A peculiar cluster of repeating low-frequency seismic events was recorded on the south flank of Katla volcano (Iceland) from 2011. As the hypocentres are located at the rim of the glacier, the seismicity may be due to volcanic or glacial processes. Information on the size and shape of the cluster may help constraining the source process. The extreme similarity of waveforms points to a very small spatial distribution of hypocentres. In order to extract meaningful information about size and shape of the cluster, we minimize uncertainty by optimizing the cross-correlation measurements and relative-relocation process. With a synthetic test we determine the best parameters for differential-time measurements and estimate their uncertainties, specifically for each waveform. We design a relocation strategy to work without a predefined velocity model, by formulating and inverting the problem to seek changes in both location and slowness, thus accounting for azimuth, take-off angles and velocity deviations from a 1D model. We solve the inversion explicitly in order to propagate data errors through the calculation. With this approach we are able to resolve a source volume few tens of meters wide on horizontal directions and around 100 meters in depth. There is no suggestion that the hypocentres lie on a single fault plane and the depth distribution indicates that their source is unlikely to be related to glacial processes as the ice thickness is not expected to exceed few tens of meters in the source area. Text glacier Iceland Katla DataCite Metadata Store (German National Library of Science and Technology) Katla ENVELOPE(-19.062,-19.062,63.631,63.631) |
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DataCite Metadata Store (German National Library of Science and Technology) |
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Geophysics physics.geo-ph FOS Physical sciences |
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Geophysics physics.geo-ph FOS Physical sciences Sgattoni, Giulia Guðmundsson, Ólafur Einarsson, Páll Lucchi, Federico Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
topic_facet |
Geophysics physics.geo-ph FOS Physical sciences |
description |
Relative relocation methods are commonly used to precisely relocate earthquake clusters consisting of similar waveforms. Repeating waveforms are often recorded at volcanoes, where, however, the crust structure is expected to contain strong heterogeneities and therefore the 1D velocity model assumption that is made in most location strategies is not likely to describe reality. A peculiar cluster of repeating low-frequency seismic events was recorded on the south flank of Katla volcano (Iceland) from 2011. As the hypocentres are located at the rim of the glacier, the seismicity may be due to volcanic or glacial processes. Information on the size and shape of the cluster may help constraining the source process. The extreme similarity of waveforms points to a very small spatial distribution of hypocentres. In order to extract meaningful information about size and shape of the cluster, we minimize uncertainty by optimizing the cross-correlation measurements and relative-relocation process. With a synthetic test we determine the best parameters for differential-time measurements and estimate their uncertainties, specifically for each waveform. We design a relocation strategy to work without a predefined velocity model, by formulating and inverting the problem to seek changes in both location and slowness, thus accounting for azimuth, take-off angles and velocity deviations from a 1D model. We solve the inversion explicitly in order to propagate data errors through the calculation. With this approach we are able to resolve a source volume few tens of meters wide on horizontal directions and around 100 meters in depth. There is no suggestion that the hypocentres lie on a single fault plane and the depth distribution indicates that their source is unlikely to be related to glacial processes as the ice thickness is not expected to exceed few tens of meters in the source area. |
format |
Text |
author |
Sgattoni, Giulia Guðmundsson, Ólafur Einarsson, Páll Lucchi, Federico |
author_facet |
Sgattoni, Giulia Guðmundsson, Ólafur Einarsson, Páll Lucchi, Federico |
author_sort |
Sgattoni, Giulia |
title |
Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
title_short |
Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
title_full |
Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
title_fullStr |
Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
title_full_unstemmed |
Relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on Katla volcano's south-flank (Iceland) |
title_sort |
relative relocation of earthquakes without a predefined velocity model: an example from a peculiar seismic cluster on katla volcano's south-flank (iceland) |
publisher |
arXiv |
publishDate |
2016 |
url |
https://dx.doi.org/10.48550/arxiv.1603.09253 https://arxiv.org/abs/1603.09253 |
long_lat |
ENVELOPE(-19.062,-19.062,63.631,63.631) |
geographic |
Katla |
geographic_facet |
Katla |
genre |
glacier Iceland Katla |
genre_facet |
glacier Iceland Katla |
op_relation |
https://dx.doi.org/10.1093/gji/ggw331 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1603.09253 https://doi.org/10.1093/gji/ggw331 |
_version_ |
1766009768006123520 |