Analysis of Off-axis, Low-velocity Zones on the Flanks of the Endeavour Segment of the Juan de Fuca Ridge
| dc.contributor.advisor | Hooft, Emilie | en_US |
| dc.contributor.author | Wells, Anne | en_US |
| dc.creator | Wells, Anne | en_US |
| dc.date.accessioned | 2012-10-24T22:23:42Z | |
| dc.date.available | 2012-10-24T22:23:42Z | |
| dc.date.issued | 2012 | |
| dc.description.abstract | Seismic data from the intermediate-spreading Endeavour segment of the Juan de Fuca Ridge reveal several crustal-level, low-velocity, high-attenuation regions on the eastern and western ridge flanks 7 to 16 km from the neovolcanic zone. I examine Pg amplitude anomalies for a wide variety of source-receiver azimuths in the Endeavour active source seismic tomography data. I use finite difference waveform forward modeling to estimate the dimensions, depth, and seismic properties of the best-observed inferred anomalous regions. The attenuating regions extend 10-15 km beneath axis-parallel bathymetric highs and from 2 to 4 km below the seafloor. The velocity reduction is small (~8%) and the attenuation large (QP ≈ 8-40) suggesting the presence of partial melt. I infer that melt focusing toward the neovolcanic zone is incomplete and that tectonic interactions with the Heckle seamount chain and/or the large segment-bounding overlapping spreading centers may promote off-axis melt delivery at the Endeavour segment. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/12319 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | University of Oregon | en_US |
| dc.rights | All Rights Reserved. | en_US |
| dc.subject | Geology | en_US |
| dc.subject | Geophysics | en_US |
| dc.subject | Magma | en_US |
| dc.subject | Marine | en_US |
| dc.subject | Seismology | en_US |
| dc.title | Analysis of Off-axis, Low-velocity Zones on the Flanks of the Endeavour Segment of the Juan de Fuca Ridge | en_US |
| dc.type | Electronic Thesis or Dissertation | en_US |
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