Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern
The work in this thesis concentrates on Katla volcano in southern Iceland. This is one of Europe’s most active volcanoes and its history tells us that it poses many threats to society, both locally (Iceland) and on a broader scale (Europe). Its geological setting is complex, where the effects of a m...
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Uppsala universitet, Institutionen för geovetenskaper
2016
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ftuppsalauniv:oai:DiVA.org:uu-303342 2023-05-15T16:48:04+02:00 Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern Jeddi, Zeinab 2016 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303342 eng eng Uppsala universitet, Institutionen för geovetenskaper Uppsala Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 1430 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303342 urn:isbn:978-91-554-9696-8 info:eu-repo/semantics/openAccess Volcano tomography volcano seismicity Katla volcano Earthquake location Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2016 ftuppsalauniv 2023-02-23T21:36:41Z The work in this thesis concentrates on Katla volcano in southern Iceland. This is one of Europe’s most active volcanoes and its history tells us that it poses many threats to society, both locally (Iceland) and on a broader scale (Europe). Its geological setting is complex, where the effects of a melting anomaly in the mantle and a changing rift geometry, perturb the classical setting of volcanism in a rifting setting. The work has focused on two aspects. The first is the varying distribution of physical properties in the subsurface around the volcano. The second is the distribution of microearthquakes around the volcano. The physical properties that we study are the speeds of seismic waves that reflect variations of temperature, composition and fracturing of the rocks. These can, therefore, help us learn about long-term processes in the volcano. The seismicity gives shorter-term information about deformation associated with current processes. I have applied two tomographic techniques to study Katla’s subsurface to a depth of 5-10 km, namely local-earthquake and ambient-noise tomography. The former makes use of the timing of waves generated by local earthquakes to constrain the earthquakes’ locations and the distribution of wave speed. Here I have concentrated on compressional waves or P waves with a typical frequency content around 10 Hz. With the latter, surface waves are extracted from microseismic noise that is generated far away at sea and their timing is measured to constrain their wave-speed distribution, which then is used to map shear-wave velocity variations. This is done at a typical frequency of 0.3 Hz. I find that the volcano contains rocks of higher velocity than its surroundings, that Katla’s caldera is underlain by low velocities at shallow depth that may be explained by hot or partially molten rocks and that beneath the caldera lies a volume of particularly high velocities that may constitute differentiated cumulates. But, I also find that it is not simple to compare results from such different ... Doctoral or Postdoctoral Thesis Iceland Katla Uppsala University: Publications (DiVA) Katla ENVELOPE(-19.062,-19.062,63.631,63.631) |
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collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Volcano tomography volcano seismicity Katla volcano Earthquake location |
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Volcano tomography volcano seismicity Katla volcano Earthquake location Jeddi, Zeinab Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
topic_facet |
Volcano tomography volcano seismicity Katla volcano Earthquake location |
description |
The work in this thesis concentrates on Katla volcano in southern Iceland. This is one of Europe’s most active volcanoes and its history tells us that it poses many threats to society, both locally (Iceland) and on a broader scale (Europe). Its geological setting is complex, where the effects of a melting anomaly in the mantle and a changing rift geometry, perturb the classical setting of volcanism in a rifting setting. The work has focused on two aspects. The first is the varying distribution of physical properties in the subsurface around the volcano. The second is the distribution of microearthquakes around the volcano. The physical properties that we study are the speeds of seismic waves that reflect variations of temperature, composition and fracturing of the rocks. These can, therefore, help us learn about long-term processes in the volcano. The seismicity gives shorter-term information about deformation associated with current processes. I have applied two tomographic techniques to study Katla’s subsurface to a depth of 5-10 km, namely local-earthquake and ambient-noise tomography. The former makes use of the timing of waves generated by local earthquakes to constrain the earthquakes’ locations and the distribution of wave speed. Here I have concentrated on compressional waves or P waves with a typical frequency content around 10 Hz. With the latter, surface waves are extracted from microseismic noise that is generated far away at sea and their timing is measured to constrain their wave-speed distribution, which then is used to map shear-wave velocity variations. This is done at a typical frequency of 0.3 Hz. I find that the volcano contains rocks of higher velocity than its surroundings, that Katla’s caldera is underlain by low velocities at shallow depth that may be explained by hot or partially molten rocks and that beneath the caldera lies a volume of particularly high velocities that may constitute differentiated cumulates. But, I also find that it is not simple to compare results from such different ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Jeddi, Zeinab |
author_facet |
Jeddi, Zeinab |
author_sort |
Jeddi, Zeinab |
title |
Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
title_short |
Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
title_full |
Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
title_fullStr |
Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
title_full_unstemmed |
Seismological Investigation of Katla Volcanic System (Iceland) : 3D Velocity Structure and Overall Seismicity Pattern |
title_sort |
seismological investigation of katla volcanic system (iceland) : 3d velocity structure and overall seismicity pattern |
publisher |
Uppsala universitet, Institutionen för geovetenskaper |
publishDate |
2016 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303342 |
long_lat |
ENVELOPE(-19.062,-19.062,63.631,63.631) |
geographic |
Katla |
geographic_facet |
Katla |
genre |
Iceland Katla |
genre_facet |
Iceland Katla |
op_relation |
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 1430 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303342 urn:isbn:978-91-554-9696-8 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766038196003536896 |