Low-velocity zone - Wikipedia
网页The low-velocity zone (LVZ) occurs close to the boundary between the lithosphere and the asthenosphere in the upper mantle. It is characterized by unusually low seismic shear wave velocity compared to the surrounding depth intervals. This range of depths also corresponds to anomalously high electrical conductivity.
Seismic low-velocity equatorial torus in the Earth’s outer core ...
网页2024年8月30日 · We constrain a torus structure at low latitudes with ~2% lower velocity than the surrounding liquid outer core via waveform modeling. We propose a thermochemical origin for such a low-velocity torus, providing important constraints on the dynamical processes of the Earth’s outer core.
低速区 - 维基百科，自由的百科全书
网页低速区 （LVZ）是 上地幔 接近 岩石圈 与 软流圈 边界处， 地震波 横波速度显著偏低、电导率显著偏高的区域。 深度从80km至300km。 其中部分区域的地震波纵波缺失。 [2][2][3][4] 另外一个地震波速显著降低的区域在 核幔邊界 的不超过50km的薄层，称为 超低速区 （英语：Ultra low velocity zone） （ULVZ）。 [3] 低速区可以用 部分熔融 （约1%）解释。 [2] 水可以降低熔点，扮演了重要角色。 [4][5] 地震横波在3个地质省的差别：TNA=北美板 …
Ultralow velocity zones in the deep Earth | Nature Geoscience
网页2024年4月12日 · Sebastian Rost: Ultralow velocity zones (ULVZs) are small patches in the Earth’s lowermost mantle, with maximum lateral dimensions of a few hundred kilometers and a few low-tens of kilometers...
Large low-shear-velocity provinces - Wikipedia
网页These provinces are characterized by slow shear wave velocities and were discovered by seismic tomography of deep Earth. There are two main provinces: the African LLSVP and the Pacific LLSVP, both extending laterally for thousands of kilometers and possibly up to 1,000 kilometres vertically from the core–mantle boundary.
Asthenospheric low-velocity zone consistent with globally …
网页2023年2月6日 · We present globally widespread evidence for a positive seismic-velocity gradient at depths of ~150 km, which represents the base of a particularly low-velocity zone within the asthenosphere.
Compositionally-distinct ultra-low velocity zones on Earth’s core ...
网页2017年8月2日 · Ultralow velocity zones (ULVZs) are mapped as geographically isolated zones of seismic anomalies detected on the core-mantle boundary (CMB) 1, 2 with a significant reduction of seismic velocity...
Low Velocity Zone - an overview | ScienceDirect Topics
网页The low-velocity zone (LVZ) in the upper mantle is characterized by low seismic wave velocities, high seismic energy attenuation, and high electrical conductivity. The bottom of the LVZ, sometimes referred to as the Lehmann discontinuity, has been identified from the study of surface wave and S-wave data in some continental areas ( Figure 4.1 ...
Low‐Velocity Structure of Subducted Oceanic Crust in the Upper …
网页2023年12月19日 · Complete dehydration of lawsonite accompanied by the gradual decarbonization of the subducted oceanic crust explains the absence of low-velocity anomalies below 300-km depth. Our findings help for a better understanding of the possible influence of carbon and water on seismic velocities of the mantle.
Seismic imaging of a mid-crustal low-velocity layer beneath the ...
网页2020年11月1日 · Low-velocity layer (LVL) within the continental crust is usually closely associated with tectonic events, thus it may reflect ongoing processes or offer a chance to backtrack the evolutional history. Mid-crustal LVL has been reported in the northern coast of the South China Sea (SCS) by several geophysical studies, but the 3D distribution of ...