Related Experiment Video
Updated: Jul 30, 2025

Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
Ultra-low-velocity anomaly inside the Pacific Slab near the 410-km discontinuity
Jiaqi Li1,2, Thomas P Ferrand3, Tong Zhou1,2,4
1Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824 USA.
Abstract:
The upper boundary of the mantle transition zone, known as the "410-km discontinuity", is attributed to the phase transformation of the mineral olivine (α) to wadsleyite (β olivine). Here we present observations of triplicated P-waves from dense seismic arrays that constrain the structure of the subducting Pacific slab near the 410-km discontinuity beneath the northern Sea of Japan. Our analysis of P-wave travel times and waveforms at periods as short as 2 s indicates the presence of an ultra-low-velocity layer within the cold slab, with a P-wave velocity that is at least ≈20% lower than in the ambient mantle and an apparent thickness of ≈20 km along the wave path. This ultra-low-velocity layer could contain unstable material (e.g., poirierite) with reduced grain size where diffusionless transformations are favored.
More Related Videos
Related Concept Videos
Magnetostatic Boundary Conditions
Significance of Displacement Current
Displacement Current
Boundary Layer Characteristics
Region of Convergence of Laplace Tarnsform
Consider a decaying exponential signal that begins at a specific time. When deriving its Laplace transform, the time-domain variable is replaced with a complex variable. This...
Uniform Depth Channel Flow

