Results 21 to 30 of about 121 (99)

From Subduction to LLSVP: The Core‐Mantle Boundary Heterogeneities Across North Atlantic

Geochemistry, Geophysics, Geosystems, 2022
The distribution of Ultra‐low Velocity Zones (ULVZs) is generally associated with the Large Low Shear Velocity Zones (LLSVPs). However, subducted slabs may be important for the characteristics of the ULVZs as well.
An Fan, Xinlei Sun, Zhou Zhang, Peng Zhang, Jianye Zong   +4 more
doaj   +1 more source

Elastic Properties of the Pyrite‐Type FeOOH‐AlOOH System From First‐Principles Calculations

Geochemistry, Geophysics, Geosystems, 2021
The stability, structure, and elastic properties of pyrite‐type (FeS2 structured) FeO2H were determined using density functional theory‐based computations with an internally consistent Coulombic self‐interaction term (Ueff). The properties of pyrite‐type
Elizabeth C. Thompson, Andrew J. Campbell, Jun Tsuchiya   +2 more
doaj   +1 more source

Elastic properties of ferropericlase at lower mantle conditions and its relevance to ULVZs

Earth and Planetary Science Letters, 2015
AbstractThe elasticity of FexMg1−xO was examined under lowermost mantle temperature and pressure conditions using density functional theory (DFT). The addition of iron decreases the shear modulus of MgO but has varying effects on the bulk modulus depending on the spin state of the iron.
Muir, Joshua M.R., Brodholt, John P.
openaire   +3 more sources

Temperature Heterogeneity in the Mantle Transition Zone Beneath the North Atlantic Region and the Highly Tilted Iceland Plume: Evidence From Receiver Functions

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 5, May 2026.
Abstract The Iceland Plume, a hot upwelling from the Earth's deep mantle, is thought to have caused high mantle temperatures beneath Iceland and its surroundings resulting in voluminous volcanism, from the North Atlantic Igneous Province at 60 Ma to the present.
Thomas A. J. Merry, Sergei Lebedev, Sanne Cottaar, Janneke I. de Laat, Christopher J. Bean, Brian M. O’Reilly   +5 more
wiley   +1 more source

Global Presence and Absence of Ultra‐Low Velocity Zones as Seen by Sdiff Postcursors

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 4, April 2026.
Abstract The core‐mantle boundary (CMB) is a region of significant lateral heterogeneity. Two antipodal large low‐velocity provinces (LLVPs) dominate the lower mantle, while smaller but more extreme ultralow velocity zones (ULVZs) are scattered atop the CMB in a variety of morphologies.
J. R. Atkins, C. Martin, S. Cottaar
wiley   +1 more source

Evidence of a ULVZ near Vanuatu from Sdiff postcursors

Journal of Studies of Earth’s Deep Interior
Thin anomalous structures known as ultra-low velocity zones (ULVZs) have been found on the core-mantle boundary (CMB) and have extreme velocity reductions. These features are detected due to their effect on seismic waves that travel through them, typically producing precursors or postcursors.
Martin, Carl, Harmsma, Lobke, Atkins, James, Deuss, Arwen, Cottaar, Sanne   +4 more
openaire   +3 more sources

Decadal Stability of Multi‐Scale Core‐Mantle Boundary in Core‐Reflections of Repeating Earthquakes

Geophysical Research Letters, Volume 53, Issue 5, 16 March 2026.
Abstract Temporal changes near the core‐mantle boundary (CMB) would trigger insights into ongoing thermal and chemical interactions between the Earth's core and mantle. Here, we search for multidecadal temporal changes in the CMB topography and heterogeneity using waveform similarity analysis of core‐reflected phases (PcP, ScP, and ScS) from global ...
Tianyu Cui, Wei Wang, John E. Vidale, Hao Zhang, Hao Luo, Yinshuang Ai   +5 more
wiley   +1 more source

Seismic Waveform Inversion for 3‐D S‐ and P‐Wave Velocity Structure in D″ Beneath Central America and the Caribbean: Evidence for Chemical Heterogeneity Due To MORB Accumulation

Journal of Geophysical Research: Solid Earth, Volume 130, Issue 10, October 2025.
Abstract We perform inversion of seismic waveforms for three‐dimensional (3‐D) models of shear and compressional seismic wave velocities (VS ${V}_{S}$ and VP ${V}_{P}$, respectively) in the lowermost 400 km of the mantle (the D″ region) beneath Central America and the Caribbean. We use data primarily from USArray stations.
Rei Sato, Kenji Kawai, Robert J. Geller
wiley   +1 more source

Global Search of PKP Precursors With Graph Neural Network: Implications for Scatterers in the Lowermost Mantle

Geophysical Research Letters, Volume 52, Issue 17, 16 September 2025.
Abstract Seismic waves preceding the core phase PKIKP, known as PKP precursors, have been used to map small scatterers near the core‐mantle boundary (CMB). However, their low signal‐to‐noise ratio has required manual identification, hindering systematic and comprehensive analysis.
Shang Ma, Zefeng Li, Daoyuan Sun, Yulong Su, Jiewen Li, Xu Si, Jun Zhu   +6 more
wiley   +1 more source

The Influence of ɛ‐to‐Py FeOOH Phase Transition on the Lower Mantle Heterogeneities

Geochemistry, Geophysics, Geosystems, Volume 26, Issue 9, September 2025.
Abstract Hydrous minerals transported by cold subducting slabs to the lowermost mantle are believed to significantly influence mantle properties and the heterogeneities in the core‐mantle boundary (CMB) region. FeOOH is one of the essential iron‐bearing hydrous minerals whose high‐pressure phases, ε‐FeOOH and Pyrite‐type FeOOH (Py‐FeOOH), can remain ...
Sparsh Sharma, Gaurav Shukla
wiley   +1 more source