Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland
Earthquake catalogues are usually dominated by diffusive behaviour consistent with the Omori law of aftershocks. This is investigated in terms of waiting times, i.e. the time between successive events in a time-sorted earthquake catalogue. The theoretical waiting time probability distribution for th...
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Uppsala universitet, Geofysik
2009
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ftuppsalauniv:oai:DiVA.org:uu-100771 2024-05-19T07:40:45+00:00 Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland Jónsdóttir, KristÃn 2009 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100771 eng eng Uppsala universitet, Geofysik Uppsala : Acta Universitatis Upsaliensis Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 636 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100771 urn:isbn:978-91-554-7500-0 info:eu-repo/semantics/openAccess Geophysics Geofysik Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2009 ftuppsalauniv 2024-04-30T23:36:01Z Earthquake catalogues are usually dominated by diffusive behaviour consistent with the Omori law of aftershocks. This is investigated in terms of waiting times, i.e. the time between successive events in a time-sorted earthquake catalogue. The theoretical waiting time probability distribution for the Omori law is derived and shown to predict the numerically produced Omori aftershock sequence well. These results enhance our understanding of aftershock processes and demonstrate that previous waiting time interpretations were severely flawed. Iceland earthquake catalogues are studied in terms of waiting times. Omori aftershock sequences are shown to predict most datasets well but there are some significant exceptions. One of these is data from the glacier covered Katla volcano in South Iceland, with few aftershocks. This dataset can be further split into two geographical groups: Several hundred volcano-tectonic earthquakes occurring within the caldera, reaching depths down to 15 km, and thousands of emergent low frequency earthquakes with a poorly defined shallow source in Goðabunga, in the western part of Katla. These events are investigated further. The lp events at Goðabunga have been recorded for decades and show a clear seasonal and climate-related correlation where their number increases in the autumn as well as during warmer years. Many of them form groups with very with similar waveforms. New broad-band seismic data suggests that the lp events originate in a steep outlet glacier covering Katla. Here, ice movement leads to ice falls over the steep escarpment, and we now believe that the lp events are generated by large ice falls rather than being related to gas or magma movements within the volcano, and are not precursors to an eruption as previously suspected. This observation probably has major significance for hazard estimation at the many ice-covered volcanoes around the world. We report near-field (vlp) signals simultaneous with the largest lp events. Our data is partly consistent in character with ... Doctoral or Postdoctoral Thesis glacier Iceland Katla Uppsala University: Publications (DiVA) |
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Uppsala University: Publications (DiVA) |
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English |
topic |
Geophysics Geofysik |
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Geophysics Geofysik Jónsdóttir, KristÃn Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
topic_facet |
Geophysics Geofysik |
description |
Earthquake catalogues are usually dominated by diffusive behaviour consistent with the Omori law of aftershocks. This is investigated in terms of waiting times, i.e. the time between successive events in a time-sorted earthquake catalogue. The theoretical waiting time probability distribution for the Omori law is derived and shown to predict the numerically produced Omori aftershock sequence well. These results enhance our understanding of aftershock processes and demonstrate that previous waiting time interpretations were severely flawed. Iceland earthquake catalogues are studied in terms of waiting times. Omori aftershock sequences are shown to predict most datasets well but there are some significant exceptions. One of these is data from the glacier covered Katla volcano in South Iceland, with few aftershocks. This dataset can be further split into two geographical groups: Several hundred volcano-tectonic earthquakes occurring within the caldera, reaching depths down to 15 km, and thousands of emergent low frequency earthquakes with a poorly defined shallow source in Goðabunga, in the western part of Katla. These events are investigated further. The lp events at Goðabunga have been recorded for decades and show a clear seasonal and climate-related correlation where their number increases in the autumn as well as during warmer years. Many of them form groups with very with similar waveforms. New broad-band seismic data suggests that the lp events originate in a steep outlet glacier covering Katla. Here, ice movement leads to ice falls over the steep escarpment, and we now believe that the lp events are generated by large ice falls rather than being related to gas or magma movements within the volcano, and are not precursors to an eruption as previously suspected. This observation probably has major significance for hazard estimation at the many ice-covered volcanoes around the world. We report near-field (vlp) signals simultaneous with the largest lp events. Our data is partly consistent in character with ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Jónsdóttir, KristÃn |
author_facet |
Jónsdóttir, KristÃn |
author_sort |
Jónsdóttir, KristÃn |
title |
Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
title_short |
Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
title_full |
Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
title_fullStr |
Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
title_full_unstemmed |
Studies of Unusual Seismicity and Long Period Events at the Glacier Overlain Katla Volcano, Iceland |
title_sort |
studies of unusual seismicity and long period events at the glacier overlain katla volcano, iceland |
publisher |
Uppsala universitet, Geofysik |
publishDate |
2009 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100771 |
genre |
glacier Iceland Katla |
genre_facet |
glacier Iceland Katla |
op_relation |
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 636 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100771 urn:isbn:978-91-554-7500-0 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1799480320430440448 |