TY - JOUR T1 - A Seismic Tomography, Gravity, and Flexure Study of the Crust and Upper Mantle Structure of the Emperor Seamounts at Jimmu Guyot JF - Journal of Geophysical Research: Solid Earth Y1 - 2022 A1 - Xu, C. A1 - Dunn, R. A. A1 - Watts, A. B. A1 - Shillington, D. J. A1 - Grevemeyer, I. A1 - Gómez de la Peña, L. A1 - Boston, B. B. KW - Emperor Seamounts KW - gravity modeling KW - oceanic crust KW - plate flexure KW - seamount structure KW - seismic tomography 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. VL - 127 UR - https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB023241 N1 - _eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB023241 ER -