Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography
Our global society is affected by, and makes use of, many time-varying processes. Processes related to geothermal energy and CO2 sequestration can help mitigate climate change and reduce the number of premature deaths (millions annually) due to air pollution from fossil fuels. Processes related to v...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Uppsala universitet, Institutionen för geovetenskaper
2022
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482658 |
id |
ftuppsalauniv:oai:DiVA.org:uu-482658 |
---|---|
record_format |
openpolar |
spelling |
ftuppsalauniv:oai:DiVA.org:uu-482658 2023-05-15T16:52:21+02:00 Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography Hobé, Alex 2022 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482658 eng eng Uppsala universitet, Institutionen för geovetenskaper Uppsala University Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 2181 orcid:0000-0002-3289-7719 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482658 urn:isbn:978-91-513-1580-5 info:eu-repo/semantics/openAccess Time-Dependent Tomography Joint Inversion Geothermal Energy Volcanotectonics Seismic Unrest Fagradalsfjall Eruption Geophysics Geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2022 ftuppsalauniv 2023-02-23T22:00:37Z Our global society is affected by, and makes use of, many time-varying processes. Processes related to geothermal energy and CO2 sequestration can help mitigate climate change and reduce the number of premature deaths (millions annually) due to air pollution from fossil fuels. Processes related to volcanic hazards instead endanger lives and infrastructure in the form of e.g. eruptions, earthquakes, and toxic gases. The related time-varying processes have changing signatures, with specific starting and ending points, and associated time frames, and are investigated in this dissertation using seismicity and time-dependent tomography (TDT). TDT has been used to, e.g., investigate pre-, syn, and post-eruptive periods in volcanic settings, as well as the stimulation of an enhanced geothermal system. One cannot, however, simply produce results for individual epochs and interpret them. We show how artificial differences between results can arise for such individual inversions, as well as for a joint inversion of asynchronous data, and when using constraints (e.g. inter-model minimization). A pragmatic method is presented to identify whether the differences between results go beyond these artificial differences. The time-varying processes under investigation relate to the Reykjanes Peninsula, Iceland, which hosts multiple geothermal power plants, and was the location of several striking signals: Multi-year deformation in a volcanic system, followed by 15 months of volcanotectonic unrest, leading to the first eruption on the peninsula in ~780 years. We show that the multi-year deformation signal is related to a super-critical reservoir that could feed a new geothermal power plant, and identify 14 seismic swarms that cascade along the boundary deformation zone during movements along this zone. We also present the first ever tomographic image of a deep magma reservoir below the Reykjanes Peninsula and follow a propagating dike from the moment it ruptured this reservoir's roof until its arrest, which was followed by a ... Doctoral or Postdoctoral Thesis Iceland Uppsala University: Publications (DiVA) Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Time-Dependent Tomography Joint Inversion Geothermal Energy Volcanotectonics Seismic Unrest Fagradalsfjall Eruption Geophysics Geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap |
spellingShingle |
Time-Dependent Tomography Joint Inversion Geothermal Energy Volcanotectonics Seismic Unrest Fagradalsfjall Eruption Geophysics Geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap Hobé, Alex Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
topic_facet |
Time-Dependent Tomography Joint Inversion Geothermal Energy Volcanotectonics Seismic Unrest Fagradalsfjall Eruption Geophysics Geofysik Geosciences Multidisciplinary Multidisciplinär geovetenskap |
description |
Our global society is affected by, and makes use of, many time-varying processes. Processes related to geothermal energy and CO2 sequestration can help mitigate climate change and reduce the number of premature deaths (millions annually) due to air pollution from fossil fuels. Processes related to volcanic hazards instead endanger lives and infrastructure in the form of e.g. eruptions, earthquakes, and toxic gases. The related time-varying processes have changing signatures, with specific starting and ending points, and associated time frames, and are investigated in this dissertation using seismicity and time-dependent tomography (TDT). TDT has been used to, e.g., investigate pre-, syn, and post-eruptive periods in volcanic settings, as well as the stimulation of an enhanced geothermal system. One cannot, however, simply produce results for individual epochs and interpret them. We show how artificial differences between results can arise for such individual inversions, as well as for a joint inversion of asynchronous data, and when using constraints (e.g. inter-model minimization). A pragmatic method is presented to identify whether the differences between results go beyond these artificial differences. The time-varying processes under investigation relate to the Reykjanes Peninsula, Iceland, which hosts multiple geothermal power plants, and was the location of several striking signals: Multi-year deformation in a volcanic system, followed by 15 months of volcanotectonic unrest, leading to the first eruption on the peninsula in ~780 years. We show that the multi-year deformation signal is related to a super-critical reservoir that could feed a new geothermal power plant, and identify 14 seismic swarms that cascade along the boundary deformation zone during movements along this zone. We also present the first ever tomographic image of a deep magma reservoir below the Reykjanes Peninsula and follow a propagating dike from the moment it ruptured this reservoir's roof until its arrest, which was followed by a ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Hobé, Alex |
author_facet |
Hobé, Alex |
author_sort |
Hobé, Alex |
title |
Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
title_short |
Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
title_full |
Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
title_fullStr |
Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
title_full_unstemmed |
Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography |
title_sort |
investigating time-varying processes using seismicity and time-dependent tomography |
publisher |
Uppsala universitet, Institutionen för geovetenskaper |
publishDate |
2022 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482658 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Reykjanes |
geographic_facet |
Reykjanes |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 2181 orcid:0000-0002-3289-7719 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-482658 urn:isbn:978-91-513-1580-5 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766042533332254720 |