Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth
As the Pacific tectonic plate passes over the Hawaiian mantle plume it builds a chain of volcanoes that press the Earth’s surface down by a few kilometers. The degree of deformation depends on the weight of the volcanoes and the strength of the plate.
In their companion papers, MacGregor et al. [2023] and Dunn et al. [2024] present new and detailed seismic studies of the volcanic loads and resulting flexure at two points crossing the Hawaiian volcanic chain. The authors find that the volcanic loads to the west of Hawaii are largely compensated by flexure. Comparisons to results from the Emperor Seamount Chain, where the plate was younger at the time of loading, confirm that near Hawaii the plate has a relatively stronger rigidity. However, isostatic compensation may not yet be complete at the youngest end of the ridge.
The absence of an accumulation of magma beneath the oceanic crust, as was previously inferred for Hawaii and at other seamounts, contradicts the expectation that underplating is favored for seamounts growing on an older tectonic plate.
Citations:
MacGregor, B. G., Dunn, R. A., Watts, A. B., Xu, C., & Shillington, D. J. (2023). A seismic tomography, gravity, and flexure study of the crust and upper mantle structure of the Hawaiian Ridge: 1. Journal of Geophysical Research: Solid Earth, 128, e2023JB027218. https://doi.org/10.1029/2023JB027218
Dunn, R. A., Watts, A. B., Xu, C., & Shillington, D. J. (2024). A seismic tomography, gravity, and flexure study of the crust and upper mantle structure across the Hawaiian Ridge: 2. Ka’ena. Journal of Geophysical Research: Solid Earth, 129, e2023JB028118. https://doi.org/10.1029/2023JB028118
—Emilie Hooft, Associate Editor, JGR: Solid Earth
