Investigation Of Source Parameters Of Earthquakes In Northern Sweden
By studying the frequency domain of seismic signals generated by earthquakes, the source parameters can be recovered, i.e., the seismic moment (M0) and the stress drop (Δσ). This method is an advantage especially since if the source parameters are calculated from the time domain a full waveform inve...
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Uppsala universitet, Geofysik
2019
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ftuppsalauniv:oai:DiVA.org:uu-380133 2023-05-15T16:12:15+02:00 Investigation Of Source Parameters Of Earthquakes In Northern Sweden González-Caneda, María 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380133 eng eng Uppsala universitet, Geofysik Examensarbete vid Institutionen för geovetenskaper, 1650-6553 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380133 info:eu-repo/semantics/openAccess spectral analysis;earthquake source observations ω-2 source model moment magnitude local magnitude Northern Sweden seismicity Geophysics Geofysik Student thesis info:eu-repo/semantics/bachelorThesis text 2019 ftuppsalauniv 2023-02-23T21:49:38Z By studying the frequency domain of seismic signals generated by earthquakes, the source parameters can be recovered, i.e., the seismic moment (M0) and the stress drop (Δσ). This method is an advantage especially since if the source parameters are calculated from the time domain a full waveform inversion is needed, therefore this procedure facilitates the computation. Besides, the moment magnitude (Mw) can be calculated from the seismic moment and, in turn, the local magnitude (ML) can be obtained by using an algorithm that matches different ranges of moment magnitude with their corresponding local magnitude. In the present thesis, small to moderate earthquakes in Northern Sweden have been used to develop a code that calculates the source parameters through the fitting of five different spectral models and, this way, discerns which model obtains the best determination of the parameters. These models have been chosen in a way that we can also extract information about the attenuation. The different models are; the Brune spectral model, Boatwright spectral model, Boatwright spectral model with a fixed fall-off rate, a general form of the spectral model with quality factor equal to 1000 and a general form of the spectral model with quality factor equal to 600. Among these models, the Boatwright model with fixed fall-off rate equal to 2, has been found to give the best fit to the data used in this thesis. This might be due to the regional conditions which are the low attenuation in the crust of northern Fennoscandia and the short hypocentral distances of the studied earthquakes. The earthquakes studied in the present thesis have shown a range of magnitudes from ML 4.2 to -0.2 with radius of an assumed circular fault ranging from 269 m to 66 m. Bachelor Thesis Fennoscandia Northern Sweden Uppsala University: Publications (DiVA) Brune ENVELOPE(6.723,6.723,62.526,62.526) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
spectral analysis;earthquake source observations ω-2 source model moment magnitude local magnitude Northern Sweden seismicity Geophysics Geofysik |
spellingShingle |
spectral analysis;earthquake source observations ω-2 source model moment magnitude local magnitude Northern Sweden seismicity Geophysics Geofysik González-Caneda, María Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
topic_facet |
spectral analysis;earthquake source observations ω-2 source model moment magnitude local magnitude Northern Sweden seismicity Geophysics Geofysik |
description |
By studying the frequency domain of seismic signals generated by earthquakes, the source parameters can be recovered, i.e., the seismic moment (M0) and the stress drop (Δσ). This method is an advantage especially since if the source parameters are calculated from the time domain a full waveform inversion is needed, therefore this procedure facilitates the computation. Besides, the moment magnitude (Mw) can be calculated from the seismic moment and, in turn, the local magnitude (ML) can be obtained by using an algorithm that matches different ranges of moment magnitude with their corresponding local magnitude. In the present thesis, small to moderate earthquakes in Northern Sweden have been used to develop a code that calculates the source parameters through the fitting of five different spectral models and, this way, discerns which model obtains the best determination of the parameters. These models have been chosen in a way that we can also extract information about the attenuation. The different models are; the Brune spectral model, Boatwright spectral model, Boatwright spectral model with a fixed fall-off rate, a general form of the spectral model with quality factor equal to 1000 and a general form of the spectral model with quality factor equal to 600. Among these models, the Boatwright model with fixed fall-off rate equal to 2, has been found to give the best fit to the data used in this thesis. This might be due to the regional conditions which are the low attenuation in the crust of northern Fennoscandia and the short hypocentral distances of the studied earthquakes. The earthquakes studied in the present thesis have shown a range of magnitudes from ML 4.2 to -0.2 with radius of an assumed circular fault ranging from 269 m to 66 m. |
format |
Bachelor Thesis |
author |
González-Caneda, María |
author_facet |
González-Caneda, María |
author_sort |
González-Caneda, María |
title |
Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
title_short |
Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
title_full |
Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
title_fullStr |
Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
title_full_unstemmed |
Investigation Of Source Parameters Of Earthquakes In Northern Sweden |
title_sort |
investigation of source parameters of earthquakes in northern sweden |
publisher |
Uppsala universitet, Geofysik |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380133 |
long_lat |
ENVELOPE(6.723,6.723,62.526,62.526) |
geographic |
Brune |
geographic_facet |
Brune |
genre |
Fennoscandia Northern Sweden |
genre_facet |
Fennoscandia Northern Sweden |
op_relation |
Examensarbete vid Institutionen för geovetenskaper, 1650-6553 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380133 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1765997514119446528 |