Low-velocity zone - Wikipedia
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.
低速区 - 维基百科，自由的百科全书
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 （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=北美板块；SNA= 北美地盾； & ATL =北大西洋。 [6] 地震波的横波在低速区 …
Low Velocity Zone - an overview | ScienceDirect Topics
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 ...
2017年8月1日 · Seismic tomography reveals 2 extensive regions in the lowermost mantle, beneath Africa and the Pacific, that exhibit lower-than-average seismic wave speeds. These regions have been named the Large Low Shear Velocity Provinces (LLSVPs), and they have spatial scales on the order of 1000s and 100s of kilometers in width and height, respectively.
中国科大地球核幔边界大尺度超低速异常体结构研究获得重要进展
2022年3月1日 · 近日，中国科学技术大学地球和空间科学学院孙道远教授课题组联合瑞士伯尔尼大学Dan J. Bower，获得了位于北太平洋下方迄今为止发现的最大尺度的ULVZ的三维结构。2月24日，相关成果以“Slab control on the mega-sized North Pacific ultra-low vel
Ultralow velocity zones in the deep Earth | Nature Geoscience
2024年4月12日 · Nature Geoscience spoke with Samantha Hansen, a geophysicist at the University of Alabama and Sebastian Rost, a global seismologist at the University of Leeds about the ultralow velocity zones in...
Asthenospheric low-velocity zone consistent with globally …
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....
Ultralow Velocity Zone Locations: A Global Assessment
2018年1月19日 · Dubbed “ultra-low velocity zones”, they remain enigmatic - less than 20% of Earth's core mantle boundary has been explored in past investigations. However, this summary suggests they have a preference of being located near the margins of two much larger anomalies, continental-sized lowermost mantle low seismic wave speed provinces.
Compositionally-distinct ultra-low velocity zones on Earth’s core ...
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...
Tracking the origin of ultralow velocity zones at the base of …
2021年1月2日 · About three decades ago, seismological models showed that the base of the mantle is laterally heterogeneous, with two vast regions beneath Africa and the Pacific that exhibit lower-than-average seismic velocity, named large low shear velocity provinces (LLSVPs), and a number of scattered patches that exhibit very low seismic velocities of up to ...