Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield
Abstract We analyze envelopes of 233 and 22 M L 0.0 to M L 1.8 earthquakes induced by two geothermal stimulations in the Helsinki, Finland, metropolitan area. We separate source spectra and site terms and determine intrinsic attenuation and the scattering strength of shear waves in the 3–200 Hz freq...
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ftsubggeo:oai:e-docs.geo-leo.de:11858/11351 2024-02-11T10:03:46+01:00 Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield Eulenfeld, Tom Hillers, Gregor Vuorinen, Tommi A. T. Wegler, Ulrich 2023-04-25 https://doi.org/10.1029/2022JB025162 http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11351 eng eng doi:10.1029/2022JB025162 http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11351 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. ddc:551.22 seismic attenuation wave scattering and diffraction induced earthquakes earthquake source observations site effects Fennoscandian Shield doc-type:article 2023 ftsubggeo https://doi.org/10.1029/2022JB025162 2024-01-21T23:12:30Z Abstract We analyze envelopes of 233 and 22 M L 0.0 to M L 1.8 earthquakes induced by two geothermal stimulations in the Helsinki, Finland, metropolitan area. We separate source spectra and site terms and determine intrinsic attenuation and the scattering strength of shear waves in the 3–200 Hz frequency range using radiative transfer based synthetic envelopes. Displacement spectra yield scaling relations with a general deviation from self‐similarity, with a stronger albeit more controversial signal from the weaker 2020 stimulation. The 2020 earthquakes also tend to have a smaller local magnitude compared to 2018 earthquakes with the same moment magnitude. We discuss these connections in the context of fluid effects on rupture speed or medium properties. Site terms demonstrate that the spectral amplification relative to two reference borehole sites is not neutral at the other sensors; largest variations are observed at surface stations at frequencies larger than 30 Hz. Intrinsic attenuation is exceptionally low with <mml:semantics> Q i − 1 <mml:annotation encoding="application/x-tex"> ${Q}_{\mathrm{i}}^{-1}$</mml:annotation></mml:semantics> values down to 2.4 × 10 −5 at 20 Hz, which allows the observation of a diffuse reflection at the ∼50 km deep Moho. Scattering strength is in the range of globally observed data with <mml:semantics> Q s c − 1 <mml:annotation encoding="application/x-tex"> ${Q}_{\mathrm{s}\mathrm{c}}^{-1}$</mml:annotation></mml:semantics> between 10 −3 and 10 −4 . The application of the employed Qopen analysis program to the 2020 data in a retrospective monitoring mode demonstrates its versatility as a seismicity processing tool. The diverse results have implications for scaling relations, hazard assessment and ground motion modeling, and imaging and monitoring using ballistic and scattered wavefields in the crystalline Fennoscandian Shield environment. Plain Language Summary: We analyze seismograms from earthquakes that were induced during two ... Article in Journal/Newspaper Fennoscandian GEO-LEOe-docs (FID GEO) Journal of Geophysical Research: Solid Earth 128 4 |
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GEO-LEOe-docs (FID GEO) |
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ftsubggeo |
language |
English |
topic |
ddc:551.22 seismic attenuation wave scattering and diffraction induced earthquakes earthquake source observations site effects Fennoscandian Shield |
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ddc:551.22 seismic attenuation wave scattering and diffraction induced earthquakes earthquake source observations site effects Fennoscandian Shield Eulenfeld, Tom Hillers, Gregor Vuorinen, Tommi A. T. Wegler, Ulrich Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
topic_facet |
ddc:551.22 seismic attenuation wave scattering and diffraction induced earthquakes earthquake source observations site effects Fennoscandian Shield |
description |
Abstract We analyze envelopes of 233 and 22 M L 0.0 to M L 1.8 earthquakes induced by two geothermal stimulations in the Helsinki, Finland, metropolitan area. We separate source spectra and site terms and determine intrinsic attenuation and the scattering strength of shear waves in the 3–200 Hz frequency range using radiative transfer based synthetic envelopes. Displacement spectra yield scaling relations with a general deviation from self‐similarity, with a stronger albeit more controversial signal from the weaker 2020 stimulation. The 2020 earthquakes also tend to have a smaller local magnitude compared to 2018 earthquakes with the same moment magnitude. We discuss these connections in the context of fluid effects on rupture speed or medium properties. Site terms demonstrate that the spectral amplification relative to two reference borehole sites is not neutral at the other sensors; largest variations are observed at surface stations at frequencies larger than 30 Hz. Intrinsic attenuation is exceptionally low with <mml:semantics> Q i − 1 <mml:annotation encoding="application/x-tex"> ${Q}_{\mathrm{i}}^{-1}$</mml:annotation></mml:semantics> values down to 2.4 × 10 −5 at 20 Hz, which allows the observation of a diffuse reflection at the ∼50 km deep Moho. Scattering strength is in the range of globally observed data with <mml:semantics> Q s c − 1 <mml:annotation encoding="application/x-tex"> ${Q}_{\mathrm{s}\mathrm{c}}^{-1}$</mml:annotation></mml:semantics> between 10 −3 and 10 −4 . The application of the employed Qopen analysis program to the 2020 data in a retrospective monitoring mode demonstrates its versatility as a seismicity processing tool. The diverse results have implications for scaling relations, hazard assessment and ground motion modeling, and imaging and monitoring using ballistic and scattered wavefields in the crystalline Fennoscandian Shield environment. Plain Language Summary: We analyze seismograms from earthquakes that were induced during two ... |
format |
Article in Journal/Newspaper |
author |
Eulenfeld, Tom Hillers, Gregor Vuorinen, Tommi A. T. Wegler, Ulrich |
author_facet |
Eulenfeld, Tom Hillers, Gregor Vuorinen, Tommi A. T. Wegler, Ulrich |
author_sort |
Eulenfeld, Tom |
title |
Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
title_short |
Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
title_full |
Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
title_fullStr |
Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
title_full_unstemmed |
Induced Earthquake Source Parameters, Attenuation, and Site Effects From Waveform Envelopes in the Fennoscandian Shield |
title_sort |
induced earthquake source parameters, attenuation, and site effects from waveform envelopes in the fennoscandian shield |
publishDate |
2023 |
url |
https://doi.org/10.1029/2022JB025162 http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11351 |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_relation |
doi:10.1029/2022JB025162 http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11351 |
op_rights |
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
op_doi |
https://doi.org/10.1029/2022JB025162 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
128 |
container_issue |
4 |
_version_ |
1790600100449353728 |