Two maps showing locations of seismic arrays.
The NoMelt (left) and Juan de Fuca (right) ocean bottom seismic (OBS) arrays that situate at different seafloor ages with distinguished mantle structure. Credit: Russell and Dalton [2022], Figure 1
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth

The ability to determine both elastic and anelastic subsurface structure across oceanic basin is important to access the physical state and chemical properties of the oceanic mantle. Measuring accurate anelastic attenuation can be difficult, however, due to the seismic wavefield complexity. 

Using teleseismic Rayleigh waves recorded by the NoMelt and Juan de Fuca (JdF) plate ocean-bottom seismic (OBS) arrays as well as synthetic data, Russell and Dalton [2022] demonstrate that reliable velocity, amplification, and attenuation measurements can be made using Helmholtz tomography. The method accounts for wavefield focusing/defocusing effect through wavefront tracking where travel time and amplitude measurements are used to solve the 2D wave equation. Distinguished attenuation structure at the NoMelt and JdF sites are revealed reflecting different physical states of the oceanic asthenosphere. The observed high amplification along the low velocity JdF Ridge offers new constraints to the model of mid-ocean ridge.

Citation: Russell, J. B., & Dalton, C. A. (2022). Rayleigh wave attenuation and amplification measured at ocean-bottom seismometer arrays using Helmholtz tomography. Journal of Geophysical Research: Solid Earth, 127, e2022JB025174.

—Fan-Chi Lin, Associate Editor, Journal of Geophysical Research: Solid Earth

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