Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves
Dispersed P wave arrivals from intermediate-depth earthquakes in the Alaskan subduction zone provide insight into the low-velocity structure of the subducting oceanic crust. P wave arrivals from 41 earthquakes in the eastern section of the arc show significant guided wave dispersion, with high-frequ...
| Main Authors: | , , |
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| Format: | Journal article |
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American Geophysical Union
2018
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| _version_ | 1797085530541785088 |
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| author | Coulson, S Garth, T Rietbrock, A |
| author_facet | Coulson, S Garth, T Rietbrock, A |
| author_sort | Coulson, S |
| collection | OXFORD |
| description | Dispersed P wave arrivals from intermediate-depth earthquakes in the Alaskan subduction zone provide insight into the low-velocity structure of the subducting oceanic crust. P wave arrivals from 41 earthquakes in the eastern section of the arc show significant guided wave dispersion, with high-frequency ( > 1 Hz) energy delayed by up to 2-3 s. We simulate this dispersion using a 2-D finite difference waveform propagation model, systematically varying both P wave velocity and low-velocity layer thickness parameters to find the lowest misfit between the observed and synthetic waveforms. We infer a 6 to 10 km thick low-velocity layer with a P wave velocity contrast of 7-15% with the overriding mantle, velocities which cannot be entirely accounted for by metamorphosed mid-ocean ridge basalt compositions. We postulate that this structure is the remnant of the subducted Yakutat terrane, significantly thinned at depth by metamorphism or delamination of material during subduction. |
| first_indexed | 2024-03-07T02:09:59Z |
| format | Journal article |
| id | oxford-uuid:a04cbd57-a5ae-46be-9325-517f1582ea81 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T02:09:59Z |
| publishDate | 2018 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:a04cbd57-a5ae-46be-9325-517f1582ea812022-03-27T02:04:26ZVelocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided wavesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a04cbd57-a5ae-46be-9325-517f1582ea81Symplectic Elements at OxfordAmerican Geophysical Union2018Coulson, SGarth, TRietbrock, ADispersed P wave arrivals from intermediate-depth earthquakes in the Alaskan subduction zone provide insight into the low-velocity structure of the subducting oceanic crust. P wave arrivals from 41 earthquakes in the eastern section of the arc show significant guided wave dispersion, with high-frequency ( > 1 Hz) energy delayed by up to 2-3 s. We simulate this dispersion using a 2-D finite difference waveform propagation model, systematically varying both P wave velocity and low-velocity layer thickness parameters to find the lowest misfit between the observed and synthetic waveforms. We infer a 6 to 10 km thick low-velocity layer with a P wave velocity contrast of 7-15% with the overriding mantle, velocities which cannot be entirely accounted for by metamorphosed mid-ocean ridge basalt compositions. We postulate that this structure is the remnant of the subducted Yakutat terrane, significantly thinned at depth by metamorphism or delamination of material during subduction. |
| spellingShingle | Coulson, S Garth, T Rietbrock, A Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title | Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title_full | Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title_fullStr | Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title_full_unstemmed | Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title_short | Velocity structure of the subducted Yakutat Terrane, Alaska: Insights from guided waves |
| title_sort | velocity structure of the subducted yakutat terrane alaska insights from guided waves |
| work_keys_str_mv | AT coulsons velocitystructureofthesubductedyakutatterranealaskainsightsfromguidedwaves AT gartht velocitystructureofthesubductedyakutatterranealaskainsightsfromguidedwaves AT rietbrocka velocitystructureofthesubductedyakutatterranealaskainsightsfromguidedwaves |