TY - JOUR
T1 - A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Emperor Seamounts at Jimmu Guyot
AU - Xu, C.
AU - Dunn, R. A.
AU - Watts, A. B.
AU - Shillington, D. J.
AU - Grevemeyer, I.
AU - Gómez de la Peña, L.
AU - Boston, B. B.
N1 - Funding Information:
This research was supported by the National Science Foundation grant OCE‐1737243 to R. A. Dunn, OCE‐1737245 to D. J. Shillington, and A. B. Watts. C. Xu was supported by the China Scholarship Council under Grant 201906330037. The data processing and manuscript writing were performed while the lead author was at the University of Hawaii at Manoa.
Funding Information:
We are grateful to the officers, crew, and scientific and technical staff onboard R/V for helping make the acquisition of the seismic, bathymetry, and gravity data used in this paper possible. Cruise data are archived at dx.doi.org/10.7284/908198 . Seismic data were provided by instruments from the Ocean‐Bottom Seismic Instrument Center ( https://obsic.whoi.edu ), which is funded by the National Science Foundation and provided by GEOMAR. The OBSIC seismic data are archived at the IRIS Data Management Center ( http://service.iris.edu/fdsnws/dataselect/1/ ) and the GEOMAR seismic data are archived at PANGAEA ( https://doi.org/10.1594/PANGAEA.941101 ). Marcus G. Langseth
Publisher Copyright:
© 2022. American Geophysical Union. All Rights Reserved.
PY - 2022/6
Y1 - 2022/6
N2 - The intraplate Hawaiian-Emperor Seamount Chain has long been considered a hotspot track generated by the motion of the Pacific plate over a deep mantle plume, and an ideal feature therefore for studies of volcanic structure, magma supply, plume-crust interaction, flexural loading, and upper mantle rheology. Despite their importance as a major component of the chain, the Emperor Seamounts have been relatively little studied. In this paper, we present the results of an active-source wide-angle reflection and refraction experiment conducted along an ocean-bottom-seismograph (OBS) line oriented perpendicular to the seamount chain, crossing Jimmu guyot. The tomographic P wave velocity model, using ∼20,000 travel times from 26 OBSs, suggests that there is a high-velocity (>6.0 km/s) intrusive core within the edifice, and the extrusive-to-intrusive ratio is estimated to be ∼2.5, indicating that Jimmu was built mainly by extrusive processes. The total volume for magmatic material above the top of the oceanic crust is ∼5.3 × 104 km3, and the related volume flux is ∼0.96 m3/s during the formation of Jimmu. Under volcanic loading, the ∼5.3-km-thick oceanic crust is depressed by ∼3.8 km over a broad region. Using the standard relationships between Vp and density, the velocity model is verified by gravity modeling, and plate flexure modeling indicates an effective elastic thickness (Te) of ∼14 km. Finally, we find no evidence for large-scale magmatic underplating beneath the pre-existing crust.
AB - The intraplate Hawaiian-Emperor Seamount Chain has long been considered a hotspot track generated by the motion of the Pacific plate over a deep mantle plume, and an ideal feature therefore for studies of volcanic structure, magma supply, plume-crust interaction, flexural loading, and upper mantle rheology. Despite their importance as a major component of the chain, the Emperor Seamounts have been relatively little studied. In this paper, we present the results of an active-source wide-angle reflection and refraction experiment conducted along an ocean-bottom-seismograph (OBS) line oriented perpendicular to the seamount chain, crossing Jimmu guyot. The tomographic P wave velocity model, using ∼20,000 travel times from 26 OBSs, suggests that there is a high-velocity (>6.0 km/s) intrusive core within the edifice, and the extrusive-to-intrusive ratio is estimated to be ∼2.5, indicating that Jimmu was built mainly by extrusive processes. The total volume for magmatic material above the top of the oceanic crust is ∼5.3 × 104 km3, and the related volume flux is ∼0.96 m3/s during the formation of Jimmu. Under volcanic loading, the ∼5.3-km-thick oceanic crust is depressed by ∼3.8 km over a broad region. Using the standard relationships between Vp and density, the velocity model is verified by gravity modeling, and plate flexure modeling indicates an effective elastic thickness (Te) of ∼14 km. Finally, we find no evidence for large-scale magmatic underplating beneath the pre-existing crust.
KW - Emperor Seamounts
KW - gravity modeling
KW - oceanic crust
KW - plate flexure
KW - seamount structure
KW - seismic tomography
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U2 - 10.1029/2021JB023241
DO - 10.1029/2021JB023241
M3 - Article
AN - SCOPUS:85132892028
SN - 2169-9313
VL - 127
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
IS - 6
M1 - e2021JB023241
ER -