Results 31 to 40 of about 204 (113)

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 Hole in the Pacific LLVP and Multipathed SKS

Geosciences
In contrast to a relatively simple whole structure of the African Large Low Velocity Province (LLVP), the Mid-Pacific LLVP appears to be much more complex and likely interacts more with the down-going slab debris from the circum-Pacific subduction zones.
Daoyuan Sun
doaj   +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

Regimes of Element Transfer Between Earth's Core and Basal Magma Ocean

Journal of Geophysical Research: Solid Earth, Volume 130, Issue 7, July 2025.
Abstract Earth's accretion was highly energetic and likely involved multiple global melting events. Following the Moon‐forming giant impact, extensive mantle melting and the separation of solids and melts under deep mantle pressures likely produced a basal magma ocean (BMO) beneath the solidified mantle.
Zhongtian Zhang, Haiyang Luo, Ming Hao, Jie Deng   +3 more
wiley   +1 more source

Thermal Evolution of Planetary Interiors With a Crystallizing Basal Magma Ocean Coupled to Parameterized Mantle Convection

Journal of Geophysical Research: Planets, Volume 130, Issue 7, July 2025.
Abstract Basal magma oceans (BMOs) persisting in the silicate portion of terrestrial planets for long periods of time (> ${ >} $1 Gyr) offer the potential to reconcile unexplained contradictions between geochemical and geophysical observations, yet our knowledge of how the presence of such layers influence planetary evolution is far from mature.
Victoria Auerbach, Dave R. Stegman
wiley   +1 more source

Coupled flow and anisotropy in the UltraLow Velocity Zones [PDF]

, 2016
Seismic observations reveal a patchwork of thin and dense structures, named UltraLow Velocity Zones (ULVZs) atop the Earth's core mantle boundary. The high width to height ratio of the ULVZs, their spatial correlation with the edges of Large Low Shear ...
Drombosky, Tyler, Hier-Majumder, Saswata
core   +1 more source

Evidence for Ultra-Low Velocity Zone Genesis in Downwelling Subducted Slabs at the Core–Mantle Boundary

The Seismic Record
We investigate broadband SPdKS waveforms from earthquakes occurring beneath Myanmar. These paths sample the core–mantle boundary beneath northwestern China.
Madeleine M. Festin, Michael S. Thorne, Mingming Li   +2 more
doaj   +1 more source

Ab Initio Study of the Conductivities of B2 FeSi Under Core‐Mantle Boundary Conditions

Geophysical Research Letters, Volume 52, Issue 10, 28 May 2025.
Abstract While the ultra‐low velocity zones (ULVZs) may hold key information about deep Earth dynamics, their elusive state and origin remain enigmatic. Recent high‐pressure experiments suggest that ULVZs may originate from the B2 FeSi crystallization from the outer core. Understanding the conductivity of the B2 phase can shed light on its role in deep
Yonghui Huang, Yunguo Li, Dario Alfè, Monica Pozzo, Huaiwei Ni   +4 more
wiley   +1 more source

The core-mantle boundary region under the Gulf of Alaska : no ULVZ for shear waves [PDF]

, 2000
The Earth's core-mantle boundary (CMB) marks the boundary between the hot, molten iron core and the silicate mantle and is a thermal, chemical, and flow boundary.
Castle, John C., Hilst, R.D. van der
core